“sexual behaviour, human”的意思、由来-百科全书

sexual behaviour, human

Introduction

any activity—solitary, between two persons, or in a group—that induces sexual arousal. There are two major determinants of human sexual behaviour: the inherited sexual response patterns that have evolved as a means of ensuring reproduction and that are a part of each individual's genetic inheritance, and the degree of restraint or other types of influence exerted on the individual by society in the expression of his sexuality. The objective here is to describe and explain both sets of factors and their interaction.

It should be noted that taboos in Western culture and the immaturity of the social sciences for a long time impeded research concerning human sexual behaviour, so that by the early 20th century scientific knowledge was largely restricted to individual case histories that had been studied by such European writers as Sigmund Freud, Havelock Ellis, and Richard, freiherr von Krafft-Ebing. By the 1920s, however, the foundations had been laid for the more extensive statistical studies that were conducted before World War II in the United States. Of the two major organizations for sex study, one, the Institut für Sexualwissenschaft in Berlin (established in 1897), was destroyed by the Nazis in 1933. The other, the Institute for Sex Research (later renamed Kinsey Institute for Research in Sex, Gender, and Reproduction), begun in 1938 by the American sexologist Alfred Charles Kinsey (Kinsey, Alfred Charles) at Indiana University in Bloomington, undertook the study of human sexual behaviour. Much of the following discussion rests on the findings of the Institute for Sex Research, which comprise the most comprehensive data available. The only other country for which comprehensive data exist is Sweden.

Types of behaviour

Human sexual behaviour may conveniently be classified according to the number and gender of the participants. There is solitary behaviour involving only one individual, and there is sociosexual behaviour involving more than one person. Sociosexual behaviour is generally divided into heterosexual behaviour (male with female) and homosexual behaviour (male with male or female with female). If three or more individuals are involved it is, of course, possible to have heterosexual and homosexual activity simultaneously.

In both solitary and sociosexual behaviour there may be activities that are sufficiently unusual to warrant the label deviant behaviour. The term deviant should not be used as a moral judgment but simply as indicating that such activity is not common in a particular society. Since human societies differ in their sexual practices, what is deviant in one society may be normal in another.

Solitary behaviour

Self-masturbation is self-stimulation with the intention of causing sexual arousal and, generally, orgasm (sexual climax). Most masturbation is done in private as an end in itself but is sometimes practiced to facilitate a sociosexual relationship.

Masturbation, generally beginning at or before puberty, is very common among males, particularly young males, but becomes less frequent or is abandoned when sociosexual activity is available. Consequently, masturbation is most frequent among the unmarried. Fewer females masturbate; in the United States, roughly one-half to two-thirds have done so, as compared to nine out of ten males. Females also tend to reduce or discontinue masturbation when they develop sociosexual relationships. There is great individual variation in frequency, so that it is impractical to try to define what range could be considered “normal.”

The myth persists, despite scientific proof to the contrary, that masturbation is physically harmful. Neither is there evidence that masturbation is immature behaviour; it is common among adults deprived of sociosexual opportunities. While solitary masturbation does provide pleasure and relief from the tension of sexual excitement, it does not have the same psychological gratification that interaction with another person provides; thus, extremely few people prefer masturbation to sociosexual activity. The psychological significance of masturbation lies in how the individual regards it. For some, it is laden with guilt; for others, it is a release from tension with no emotional content; and for others it is simply another source of pleasure to be enjoyed for its own sake.

The majority of males and females have fantasies of some sociosexual activity while they masturbate. The fantasy not infrequently involves idealized sexual partners and activities that the individual has not experienced and even might avoid in real life.

Since the masturbating person is in sole control of the areas that are stimulated, the degree of pressure, and the rapidity of movement, masturbation is often more effective in producing sexual arousal and orgasm than is sociosexual activity, during which the stimulation is determined to some degree by one's partner.

Orgasm in sleep evidently occurs only in humans. Its causes are not wholly known. The idea that it results from the pressure of accumulated semen is invalid because not only do nocturnal emissions sometimes occur in males on successive nights, but females experience orgasm in sleep as well. In some cases orgasm in sleep seems a compensatory phenomenon, occurring during times when the individual has been deprived of or abstains from other sexual activity. In other cases it may result from external stimuli, such as sleeping prone or having night clothing caught between one's legs. Most orgasms during sleep are accompanied by erotic dreams.

A great majority of males experience orgasm in sleep. This almost always begins and is most frequent in adolescence, tending to disappear later in life. Fewer females have orgasm in sleep, and, unlike males, they usually begin having such experience when fully adult.

Orgasm in sleep is generally infrequent, seldom exceeding a dozen times per year for males and three or four times a year for the average female.

Most sexual arousal does not lead to sexual activity with another individual. Humans are constantly exposed to sexual stimuli when seeing attractive persons and are subjected to sexual themes in advertising and the mass media. Response to such visual and other stimuli is strongest in adolescence and early adult life and usually gradually declines with advancing age. One of the necessary tasks of growing up is learning to cope with one's sexual arousal and to achieve some balance between suppression, which can be injurious, and free expression, which can lead to social difficulties. There is great variation among individuals in the strength of sex drive and responsiveness, so this necessary exercise of restraint is correspondingly difficult or easy.

Sociosexual behaviour

By far the greatest amount of sociosexual behaviour is heterosexual behaviour between only one male and one female. Heterosexual behaviour frequently begins in childhood, and, while much of it may be motivated by curiosity, such as showing or examining genitalia, many children engage in sex play because it is pleasurable. The sexual impulse and responsiveness are present in varying degrees in most children and latent in the remainder. With adolescence, sex play is superseded by dating, which is socially encouraged, and dating almost inevitably involves some physical contact resulting in sexual arousal. This contact, labelled necking or petting, is a part of the learning process and ultimately of courtship and the selection of a marriage partner.

Petting varies from hugging, kissing, and generalized caresses of the clothed body to techniques involving genital stimulation. Petting may be done for its own sake as an expression of affection and a source of pleasure, and it may occur as a preliminary to coitus. This last form of petting is known as foreplay. In a minority of cases, but a substantial minority, petting leads to orgasm and may be a substitute for coitus. Excluding foreplay, petting is usually very stereotyped, beginning with hugging and kissing and gradually escalating to stimulation of the breasts and genitalia. In most societies petting and its escalation are initiated by the male more often than by the female, who generally rejects or accepts the male's overtures but refrains from playing a more aggressive role. Petting in some form is a near-universal human experience and is valuable not only in mate selection but as a means of learning how to interact with another person sexually.

Coitus (sexual intercourse), the insertion of the penis into the vagina, is viewed by society quite differently depending upon the marital status of the individuals. The majority of human societies permit premarital coitus, at least under certain circumstances. In more repressive societies, such as modern Western society, it is more likely to be tolerated (but not encouraged) if the individuals intend marriage. Marital coitus is usually regarded as an obligation in most societies. Extramarital coitus (adultery), particularly by wives, is generally condemned and, if permitted, is allowed only under exceptional conditions or with specified persons. Societies tend to be more lenient toward males than females regarding extramarital coitus. This double standard of morality is also seen in premarital life. Postmarital coitus (i.e., coitus by separated, divorced or widowed persons) is almost always ignored. Even societies that try to confine coitus to marriage recognize the difficulty of trying to force abstinence upon sexually experienced and usually older persons.

In the United States and much of Europe, there has been, within the last century, a progressive trend toward an increase in premarital coitus. Currently in the United States, at least three-quarters of the males and over half of the females have experienced premarital coitus. The proportions for this experience vary in different groups and socioeconomic classes. In Scandinavia, the incidence of premarital coitus is far greater, exceeding the 90 percent mark in Sweden, where it is now expected behaviour.

Extramarital coitus continues to be openly condemned but is becoming more tolerated secretly, particularly if mitigating circumstances are involved. In some areas, such as southern Europe and Latin America (Latin America, history of), extramarital coitus is expected of most husbands and is accepted by society if the behaviour is not too flagrant. The wives do not generally approve but are resigned to what they believe to be a masculine propensity. In the United States, where at least half the husbands and one-quarter of the wives have extramarital coitus at some point in their lives, there have recently developed small organizations or clubs that exist to provide extramarital coitus for married couples. Despite the publicity they have engendered, however, extremely few individuals have belonged to such organizations. Most extramarital coitus is done secretly without the knowledge of the spouse. Most husbands and wives feel very possessive of their spouses and interpret extramarital activity as an aspersion on their own sexual adequacy, as indicating a loss of affection and as being a source of social disgrace.

Human beings are not inherently monogamous (monogamy) but have a natural desire for diversity in their sexuality as in other aspects of life. Some societies have provided a release for these desires by suspending the restraints on extramarital coitus on special occasions or with certain individuals, and in modern Western society a certain amount of extramarital flirtation or mild petting at parties is not considered unusual behaviour.

Discussion of sociosexual behaviour would be incomplete without some note of the role it has played in ceremony and religion. While the major religions of today are to varying degrees antisexual, many religions have incorporated sexual behaviour into their rites (ritual) and ceremonies. Human beings' ancient and continuing interest in their own fertility and in that of food plants and animals makes such a connection between sex and religion inevitable, particularly among peoples with uncertain food supplies. In most religions the deities were considered to have active sexual lives and sometimes took a sexual interest in humans. In this regard it is noteworthy that in Christianity sexual behaviour is absent in heaven and sexual proclivities are ascribed only to evil supernatural beings: Satan, devils, incubi (incubus), and succubi (succubus) (spirits or demons who seek out sleeping humans for sexual intercourse).

Whether or not a behaviour is interpreted by society or the individual as erotic (i.e., capable of engendering sexual response) depends chiefly on the context in which the behaviour occurs. A kiss, for example, may express asexual affection (as a kiss between relatives), respect (a French officer kissing a soldier after bestowing a medal on him), reverence (kissing the hand or foot of a pope), or it may be a casual salutation and social amenity. Even something as specific as touching genitalia is not construed as sexual if done for medical reasons. In other words, the apparent motivation of the behaviour determines its interpretation.

Individuals are extremely sensitive in judging motivations: a greeting kiss, if protracted more than a second or two, takes on a sexual connotation, and recent studies show that if an adult male at a party stands closer than the length of his hand and forearm to a female, she generally imputes a sexual motive to his proximity. Nudity is construed as erotic or even as a sexual invitation—unless it occurs in a medical context, in a group consisting of but one gender, or in a nudist camp.

Physiological aspects

Sexual response

Sexual response follows a pattern of sequential stages or phases when sexual activity is continued. First, there is the excitement phase marked by increase in pulse and blood pressure, an increase in blood supply to the surface of the body resulting in increased skin temperature, flushing, and swelling of all distensible body parts (particularly noticeable in the penis and female breasts), more rapid breathing, the secretion of genital fluids, vaginal expansion, and a general increase in muscle tension. These symptoms of arousal eventually increase to a near maximal physiological level, the plateau phase, which is generally of brief duration. If stimulation is continued, orgasm usually occurs. Orgasm is marked by a feeling of sudden intense pleasure, an abrupt increase in pulse rate and blood pressure, and spasms of the pelvic muscles causing vaginal contractions in the female and ejaculation by the male. Involuntary vocalization may also occur. Orgasm lasts for a few seconds (normally not over ten), after which the individual enters the resolution phase, the return to a normal or subnormal physiological state. Up to the resolution phase, males and females are the same in their response sequence, but, whereas males return to normal even if stimluation continues, continued stimulation can produce additional orgasms in females. In brief, after one orgasm a male becomes unresponsive to sexual stimulation and cannot begin to build up another excitement phase until some period of time has elapsed, but females are physically capable of repeated orgasms without the intervening “rest period” required by males.

Genetic (genetics, human) and hormonal factors

While all normal individuals are born with the neurophysiology necessary for the sexual-response cycle described above, inheritance determines the intensity of their responses and their basic “sex drive.” There is great variation in this regard: some persons have the need for frequent sexual expressions; others require very little; and some persons respond quickly and violently, while others are slower and milder in their reactions. While the genetic basis of these differences is unknown and while such variations are obscured by conditioning, there is no doubt that sexual capacities, like all other physiological capacities, are genetically determined. It is unlikely, however, that genes control the sexual orientation of normal humans in the sense of individuals being predestined to become homosexual or heterosexual. Some severe genetic abnormality can, of course, profoundly affect intelligence, sexual capacity, and physical appearance and hence the entire sexual life.

While the normal female has 44 autosomes plus two X-chromosomes (female) and the normal male 44 autosomes plus one X-chromosome and one Y-chromosome (male), many genetic abnormalities are possible. There are females, for example, with too many X-chromosomes (44+XXX) or too few (44+X) and males with an extra female chromosome (44+XXY) or an extra male chromosome (44+XYY). No 44+YY males exist—an X-chromosome is necessary for survival, even in the womb.

One's genetic makeup determines one's hormonal status and the sensitivity of one's body to these hormones. While a disorder of any part of the endocrine system (endocrine system, human) can adversely affect sexual life, the hormones most directly influencing sexuality are the androgens (androgen) (male sex hormones), produced chiefly in the testicles (testis), and the estrogens (estrogen) (female sex hormones), produced chiefly in the ovaries (ovary). In early embryonic life there are neither testicles nor ovaries but simply two undifferentiated organs (gonads (gonad)) that can develop either into testicles or ovaries. If the embryo has a Y-chromosome, the gonads become testicles; otherwise, they become ovaries. The testicles of the fetus produce androgens, and these cause the fetus to develop male anatomy. The absence of testicles results in the development of female anatomy. Animal experiments show that, if the testicles of a male fetus are removed, the individual will develop into what seems a female (although lacking ovaries). Consequently, it has been said that humans are basically female.

After birth and until puberty, the ovaries and testicles produce comparatively few hormones, and little girls and boys are much alike in size and appearance. At puberty, however, these organs begin producing in greater abundance, with dramatic results. The androgens produced by boys cause changes in body build, greater muscular development, body and facial hair, and voice change. In girls the estrogens cause breast development, menstruation, and feminine body build. A boy castrated (castration) before puberty does not develop masculine physical characteristics and manifests in adult life more of a feminine body build, lack of masculine body and facial hair, less muscular strength, a high voice, and small genitalia. A girl who has her ovaries removed before puberty is less markedly altered but retains a childlike body build, does not develop breasts, and never menstruates. Castrated individuals or persons producing insufficient hormones can be restored to a normal condition by administration of appropriate hormones.

Beyond their role in developing the secondary sexual characteristics of the body, the hormones continue to play a role in adult life. An androgen deficiency causes a decrease in a man's sexual responsiveness, and an estrogen deficiency adversely affects a woman's fertility and causes atrophy of the genitalia. A loss of energy may also result in both men and women.

Androgen seems linked in both males and females with aggressiveness and strength of sexual drive. When androgen is given to a female in animal experiments, she becomes more aggressive and displays behaviour more typical of males—by mounting other animals, for example. Estrogen increases her sexual responsiveness and intensifies her female behaviour. Androgen given to a male often increases his sexual behaviour, but estrogen diminishes his sex drive.

In humans the picture is more complex, since human sexual behaviour and response is less dependent on hormones once adulthood has been reached. Removing androgen from an adult male reduces his sexual capacity; but this occurs gradually, and sometimes the reduction is small. Giving androgen to a normal human male generally has little or no effect since he is already producing all he can use. Giving him estrogen reduces his sex drive. Administration of androgen to an adult human female often increases her sex drive, enlarges her clitoris, and promotes the growth of facial hair. Giving estrogen to a normal woman before menopausal age generally has no effect whatsoever—probably because human females, unlike other female mammals, do not have hormonally controlled periods of “heat” (estrus).

Hormones have no connection with the sexual orientation of humans. Male homosexuals do not have more estrogens than normal males (who have a little) nor can their preferences be altered by giving them androgen.

Nervous system (nervous system, human) factors

The nervous system consists of the central nervous system and the peripheral nervous system. The brain and spinal cord constitute the central system, while the peripheral system is composed of (1) the cerebrospinal nerves that go to the spinal cord (afferent nerves), transmitting sensory stimuli and those that come from the cord (efferent nerves) transmitting impulses to activate muscles, and (2) the autonomic system (autonomic nervous system), the primary function of which is the regulation and maintenance of the body processes necessary to life, such as heart rate, breathing, digestion, and temperature control. Sexual response involves the entire nervous system. The autonomic system controls the involuntary responses; the afferent cerebrospinal nerves carry the sensory messages to the brain; the efferent cerebrospinal nerves carry commands from the brain to the muscles; and the spinal cord serves as a great transmission cable. The brain itself is the coordinating and controlling centre, interpreting what sensations are to be perceived as sexual and issuing appropriate “orders” to the rest of the nervous system.

The parts of the brain thought to be most concerned with sexual response are the hypothalamus and the limbic system, but no specialized “sex centre” has been located in the human brain. Animal experiments indicate that each individual has coded in its brain two sexual response patterns, one for mounting (masculine) behaviour and one for mounted (feminine) behaviour. The mounting pattern can be elicited or intensified by male sex hormone and the mounted pattern by female sex hormone. Normally, one response pattern is dominant and the other latent but capable of being called into action when suitable circumstances occur. The degree to which such inherent patterning exists in humans is unknown.

While the brain is normally in charge, there is some reflex (i.e., not brain-controlled) sexual response. Stimulation of the genital and perineal area can cause the “genital reflex”: erection and ejaculation in the male, vaginal changes and lubrication in the female. This reflex is mediated by the lower spinal cord, and the brain need not be involved. Of course, the brain can override and suppress such reflex activity—as it does when an individual decides that a sexual response is socially inappropriate.

Development (biological development) and change in the reproductive system

One's anatomy and sexuality change with age. The changes are rapid in intra-uterine life and around puberty but are much slower and gradual in other phases of the life cycle.

The reproductive organs first develop in the same form for both males and females: internally there are two undifferentiated gonads and two pairs of parallel ducts (Wolffian (Wolffian duct) and Müllerian ducts); externally there is a genital protrusion with a groove (urethral groove) below it, the groove being flanked by two folds (urethral folds). On either side of the genital protrusion and groove are two ridgelike swellings (labioscrotal swellings). Around the fourth week of life the gonads differentiate into either testes or ovaries. If testes develop, the hormone they secrete causes the Müllerian duct to degenerate and almost vanish and causes the Wolffian duct to elaborate into the sperm-carrying tubes and related organs (the vas deferens, epididymis, and seminal vesicles, for example). If ovaries develop, the Wolffian duct deteriorates, and the Müllerian duct elaborates to form the fallopian tubes, uterus, and part of the vagina. The external genitalia simultaneously change. The genital protrusion becomes either a penis or clitoris. In the female the groove below the clitoris stays open to form the vulva, and the folds on either side of the groove become the inner lips of the vulva (the labia minora). In the male these folds grow together, converting the groove into the urethral tube of the penis. The ridgelike swellings on either side remain apart in the female and constitute the large labia (labia majora), but in the male they grow together to form the scrotal sac into which the testes subsequently descend.

At birth both male and female have all the neurophysiological equipment necessary for sexual response, although the reproductive system is not at this stage functional. Sexual interests, sexual behaviour, and sexual response are seen with increasing frequency in most children from infancy on. Even newborn males have penile erections, and babies of both sexes seem to find pleasure in genital stimulation. What appears to be orgasm has been observed in infant boys and girls, and, later in childhood, orgasm definitely can occur in masturbation or sex play.

puberty may be defined as that short period of time (generally two years) during which the reproductive system matures and the secondary sexual characteristics appear. The ovaries and testes begin producing much larger amounts of hormones, pubic hair appears, female breasts develop, the menstrual cycle begins in females, spermatozoa and viable eggs are produced, and males experience voice change and a sudden acceleration in growth. Puberty generally occurs in females around age 12–13 and in males at about 13–14, but there is much individual variation. With puberty there is generally an intensification or the first appearance of sexual interest. Puberty marks the beginning of adolescence.

Adolescence, from a physical viewpoint, is that period between puberty and the attainment of one's maximum height. By the latter point, which occurs around age 16 in females and 18 in males, the individual has adult anatomy and physiology. In late adolescence the majority of individuals are probably at their peak in terms of sexual capacity: the ability to respond quickly and repeatedly. During this period the sex drive is at its maximum in males, although it is difficult to say whether this is also true of females, since female sexuality, in many societies, is frequently suppressed during adolescence.

Following adolescence there are about three decades of adult life during which physiological changes are slow and gradual. While muscular strength increases for a time, the changes may best be described as slow deterioration. This physical decline is not immediately evident in sexual behaviour, which often increases in quantity and quality as the individual develops more social skills and higher socio-economic status and loses some of the inhibitions (inhibition) and uncertainties that often impede adolescent sexuality. Indeed, in the case of the United States female, the deterioration (human aging) is more than offset by her gradual loss of sexual inhibition, and the effect of age is not clear until menopausal symptoms begin. In the male, however, there is no such masking of deterioration, and the frequency of sexual activity and the intensity of interest and response slowly, but inexorably, decline.

If one must arbitrarily select an age to mark the beginning of old age, 50 is appropriate. By then, most females have experienced menopausal symptoms, and most males have been forced to recognize their increasing physical limitations. With menopause, the female genitalia gradually begin to atrophy and the amount of vaginal secretion diminishes—this is the direct consequence of the cessation of ovarian function and can be prevented, or the symptoms reversed, by administering estrogen. If a female has had a good sexual adjustment prior to menopause and if she does not believe in the fallacy that it spells the end of sexual life, menopause will have no adverse effect on her sexual and orgasmic ability. There is reason to believe that if a woman remains in good health and genital atrophy is prevented, she could enjoy sexual activity regardless of age. Males in good health are also capable of continuing sexual activity, although with an ever-decreasing frequency, throughout old age. The male has more difficulty in achieving erection, cannot maintain erection as long, and must have longer and longer “rest periods” between sexual acts. The amount of ejaculate becomes less, but most old males are still fertile. The Cowper's gland (bulbourethral gland) secretion (called “precoital mucus”) diminishes or disappears entirely. According to Kinsey's data, about one-quarter of males are impotent (impotence) by age 65, one-half by age 75, and three-quarters by age 80. One must remember, however, that some unknown but certainly substantial proportion of this impotence may be attributed to poor health.

In general, the female withstands the onslaughts of age better than the male. The reduction in the frequency of marital intercourse or even its abandonment is more often than not the result of male deterioration.

Psychological aspects

Effects of early conditioning

Physiology sets only very broad limits on human sexuality; most of the enormous variation found among humans must be attributed to the psychological factors of learning and conditioning.

The human infant (infancy) is born simply with the ability to respond sexually to tactile stimulation. It is only later and gradually that the individual learns or is conditioned to respond to other stimuli, to develop a sexual attraction to males or females or both, to interpret some stimuli as sexual and others as nonsexual, and to control in some measure his or her sexual response. In other words, the general and diffuse sexuality of the infant becomes increasingly elaborated, differentiated, and specific.

The early years of life are, therefore, of paramount importance in the development of what ultimately becomes adult sexual orientation. There appears to be a reasonably fixed sequence of development. Before age five, the child develops a sense of gender identity, thinks of himself or herself as a boy or girl, and begins to relate to others differently according to their gender. Through experience the child learns what behaviour is rewarded and what is punished and what sorts of behaviour are expected of him or her. Parents, peers, and society (socialization) in general teach and condition the child about sex not so much by direct informational statements and admonitions as by indirect and often unconscious communication. The child soon learns, for example, that he can touch any part of his body or someone else's body except the anal–genital region. The child rubbing its genitals finds that this quickly attracts adult attention and admonishment or that adults will divert him or her from this activity. It becomes clear that there is something peculiar and taboo about this area of the body. This “genital taboo” is reinforced by the great concern over the child's excretory behaviour: bladder and bowel control is praised; loss of control is met by disappointment, chiding, and expressions of disgust. Obviously, the anal–genital area is not only a taboo area but a very important one as well. It is almost inevitable that the genitalia become associated with anxiety and shame. It is noteworthy that this attitude finds expression in the language of Western civilizations, as in “privates” (something to be kept hidden) and the German word for the genitals, Scham (“shame”).

While all children in Western civilizations experience this antisexual teaching and conditioning, a few have, in addition, atypical sexual experiences, such as witnessing or hearing sexual intercourse or having sexual contact with an older person. The effects of such atypical experiences depend upon how the child interprets them and upon the reaction of adults if the experience comes to their attention. Seeing parental coitus is harmless if the child interprets it as playful wrestling but harmful if he considers it as hostile, assaultive behaviour. Similarly, an experience with an adult may seem merely a curious and pointless game, or it may be a hideous trauma leaving lifelong psychic scars. In many cases the reaction of parents and society determines the child's interpretation of the event. What would have been a trivial and soon-forgotten act becomes traumatic if the mother cries, the father rages, and the police interrogate the child.

Some atypical developments occur through association during the formative years. A child may associate clothing, especially underclothing, stockings, and shoes with gender and sex and thereby establish the basis for later fetishism or transvestism. Others, having been spanked or otherwise punished for self-masturbation or childhood sex play, form an association between punishment, pain, and sex that could escalate later into sadism or masochism. It is not known why some children form such associations whereas others with apparently similar experience do not.

Around the age of puberty, parents and society, who more often than not refuse to recognize that children have sexual responses and capabilities, finally face the inescapable reality and consequently begin inculcating children with their attitudes and standards regarding sex. This campaign by adults is almost wholly negative—the child is told what not to do. While dating (courtship) may be encouraged, no form of sexual activity is advocated or held up as model behaviour. The message usually is “be popular” (i.e., sexually attractive), but abstain from sexual activity. This antisexualism is particularly intense regarding young females and is reinforced by reference to pregnancy, venereal disease, and, most importantly, social disgrace. To this list religious (religion) families add the concept of the sinfulness of premarital sexual expression. With young males the double standard of morality still prevails. The youth receives a double message, “don't do it, but we expect that you will.” No such loophole in the prohibitions is offered young girls. Meanwhile, the young male's peer group is exerting a prosexual influence, and his social status is enhanced by his sexual exploits or by exaggerated reports thereof.

As a result of this double standard of sexual morality, the relationship between young males and females often becomes a ritualized contest, the male attempting to escalate the sexual activity and the female resisting his efforts. Instead of mutuality and respect, one often has a struggle in which the female is viewed as a reluctant sexual object to be exploited, and the male is viewed as a seducer and aggressor who must succeed in order to maintain his self-image and his status with his peers. This sort of pathological relationship causes a lasting attitude on the part of females: men are not to be trusted; they are interested only in sex; a girl dare not smile or be friendly lest males interpret it as a sign of sexual availability, and so forth. Such an aura of suspicion, hostility, and anxiety is scarcely conducive to the development of warm, trusting relationships between males and females. Fortunately, love or infatuation usually overcomes this negativism with regard to particular males, but the average female still maintains a defensive and skeptical attitude toward men.

Western society is replete with attitudes that impede the development of a healthy attitude toward sex. The free abandon so necessary to a full sexual relationship is, in the eyes of many, an unseemly loss of self-control, and self-control is something one is urged to maintain from infancy onward. Panting, sweating, and involuntary vocalization are incompatible with the image of dignity. Worse yet is any substance once it has left the body: it immediately becomes unclean. The male and female genital fluids are generally regarded with disgust—they are not only excretions but sexual excretions. Here again, societal concern over excretion is involved, for sexual organs are also urinary passages and are in close proximity to the “dirtiest” of all places—the anus. Lastly, many individuals in society regard menstrual (menstruation) fluid with disgust and abstain from sexual intercourse during the four to six days of flow. This attitude is formalized in Judaism, in which menstruating females are specifically labelled as ritually unclean.

In view of all these factors working against a healthy, rational attitude toward sex and in view of the inevitable disappointments, exploitations, and rejections that are involved in human relationships, one might wonder how anyone could reach adulthood without being seriously maladjusted. The sexual impulse, however, is sufficiently strong and persistent and repeated sexual activity gradually erodes the inhibitions and any sense of guilt or shame. Further, all humans have a deep need to be esteemed, wanted, and loved. Sexual activity with another is seen as proof that one is attractive, desired, valued, and possibly loved—a proof very necessary to self-esteem and happiness. Hence, even among the very inhibited or those with weak sex drive, there is this powerful motivation to engage in sociosexual activity.

Most persons ultimately achieve at least a tolerable sexual adjustment. Some unfortunates, nevertheless, remain permanently handicapped, and very few completely escape the effects of society's antisexual conditioning. While certain inhibitions and restraints are socially and psychologically useful—such as deferring gratification until circumstances are appropriate and modifying behaviour out of regard for the feelings of others—most people labour under an additional burden of useless and deleterious attitudes and restrictions.

Sexual problems

Sexual problems may be classified as physiological, psychological, and social in origin. Any given problem may involve all three categories; a physiological problem, for example, will produce psychological effects, and these may result in some social maladjustment.

Physiological problems of a specifically sexual nature are rather few. Only a small minority of people suffer from diseases of or deficient development of the genitalia or that part of the neurophysiology governing sexual response. Many people, however, experience at some time sexual problems that are by-products of other pathologies or injuries.

Vaginal infections, for example, retroverted uteri, prostatitis, adrenal tumours, diabetes, senile changes of the vagina, and cardiovascular conditions may cause disturbance of the sexual life. In brief, anything that seriously interferes with normal bodily functioning generally causes some degree of sexual trouble. Fortunately, the great majority of physiological sexual problems are solved through medication or surgery. Generally, only those problems involving damage to the nervous system defy therapy.

Psychological (psychology) problems constitute by far the largest category. They are not only the product of socially induced inhibitions (inhibition), maladaptive attitudes, and ignorance but also of sexual myths held by society. An example of the latter is the idea that good, mature sex must involve rapid erection, protracted coitus, and simultaneous orgasm. Magazines, marriage books, and general sexual folklore reinforce these demanding ideals, which cannot always be met and hence give rise to anxiety, guilt, and feelings of inadequacy.

Premature ejaculation is a common problem, especially for young males. Sometimes this is not the consequence of any psychological problem but the natural result of excessive tension in a male who has been sexually deprived. In such cases, more frequent coitus solves the problem. Premature ejaculation is difficult to define. The best definition is that offered by the American sexologists, William Howell Masters and Virginia Eshelman Johnson, who say that a male suffers from premature ejaculation if he cannot delay ejaculation long enough to induce orgasm in a sexually normal female at least half the time. This generally means that vaginal penetration with some movement (although not continuous) must be maintained for more than one minute. The average American male ejaculates in two or three minutes after vaginal penetration, a coital duration sufficient to cause orgasm in most females the majority of the time. Various methods of preventing premature ejaculation have been tried. One is for the male to excite the female more during the foreplay so that she reaches orgasm more rapidly after penetration, but this technique often excites the male as well and defeats its purpose. Another common method is for the male to think of nonsexual matters, which may prove effective but reduces his pleasure. The most effective therapy is that advocated by Masters and Johnson in which the female brings the male nearly to orgasm and then prevents the male's orgasm by briefly compressing the penis between her fingers just below the head of the penis. The couple come to realize that premature ejaculation can thus be easily prevented, their anxiety disappears, and ultimately they can achieve normal coitus without resorting to this squeeze technique.

Erectile impotence is almost always of psychological origin in males under 40; in older males physical causes are more often involved. Fear of being impotent frequently causes impotence, and, in many cases, the afflicted male is simply caught up in a self-perpetuating problem that can be solved only by achieving a successful act of coitus. In other cases, the impotence may be the result of disinterest in the sexual partner, fatigue, distraction because of nonsexual worries, intoxication, or other causes—such occasional impotency is common and requires no therapy.

Some males, however, are chronically impotent and require psychotherapy or behaviour therapy. Such impotency is thought to be the result of deep-seated causal factors such as unconscious feelings of hostility, fear, inadequacy, or guilt. Primary impotence, the inability to ever have achieved erection sufficient for coitus, is more difficult to treat than the far more common secondary impotence, which is impotence in a male who was formerly potent.

Ejaculatory impotence, the inability to ejaculate in coitus, is quite rare and is almost always of psychogenic origin. It seems associated with ideas of contamination or with memories of traumatic experiences. Occasional ejaculatory inability may be expected in older men or in any male who has exceeded his sexual capacity.

vaginismus is a powerful spasm of the pelvic musculature constricting the vagina so that penetration is painful or impossible. It seems wholly due to antisexual conditioning or psychological trauma and serves as an unconscious defense against coitus. It is treated by psychotherapy and by gradually dilating the vagina with increasingly large cylinders.

dyspareunia, painful coitus, is generally physical rather than psychological. It is mentioned here only because some inexperienced females fear they cannot accommodate a penis without being painfully stretched. This is a needless fear since the vagina is not only highly elastic but enlarges with sexual arousal, so that even a small female can, if aroused, easily receive an exceptionally large penis.

Disparity in sexual desire constitutes the most common sexual problem. It is to some extent inescapable, since differences in the strength of the sexual impulse and the ability to respond are based on neurophysiological differences. Much disparity, however, is the result of inhibition or of one person having been subjected to more sexual stimuli during the day than the other. The partner who has been seeing sexually attractive persons periodically during the day and who may have had an opportunity to relax on the way back from the office or store is naturally more interested in coitus than the partner who has not been exposed to sexual stimuli. Another cause of disparity is a difference in viewpoint. Perhaps one person anticipates coitus as a palliative to compensate for the trials and tribulations of life, whereas another may be interested in sex only if the preceding hours have been reasonably problem-free and happy. Even in cases of neurophysiological differences in sex drive, the less-motivated partner can be trained to a higher level of interest, since most humans operate well below their sexual capacities.

Psychological fatigue, a growing disinterest in sexual behaviour with a particular partner, sometimes constitutes a problem. Humans are subject to monotony, and coitus may become routine or even a chore. Lessening frequencies of marital coitus are more often the result of this than of age. The solution lies in varying the time, the setting, and in breaking away from habitual techniques and positions.

Preferences for or antipathies toward particular positions, techniques, or times frequently cause trouble. One partner may desire mouth-genital contact or anal stimulation that the other partner finds disagreeable or perverse. Some wish to have coitus in the light, others insist upon darkness; some prefer morning, others evening. The possibilities for disagreement are legion. Even if disagreements stemming from needless inhibition are overcome, there still remain disparities in preference, and these should be met by the philosophy that, by giving pleasure to another, one obtains pleasure. Needless to say, no partner should insist upon that which is abhorrent to the other after the latter has made honest attempts to cooperate.

Lack of female orgasm, anorgasmy, is a very frequent problem. One should differentiate between females who become sexually aroused but do not reach orgasm and those who do not become aroused. Only the latter merit the label frigid (frigidity). It is common for females not to achieve orgasm during the first weeks or months of coital activity. It is almost as though many females must learn how to have orgasm, for after having had one they respond with increasing frequency. In some cases, the female initially has no idea how to copulate effectively and simply lies passive, expecting the male to bring her to orgasm. Other females resist orgasm because the feeling of being swept away and losing control is frightening. In most cases, however, anorgasmy is simply the result of years of inhibition—having been trained since childhood to avoid yielding to the sexual impulse, it is difficult to metamorphose into a responsive and orgasmic being. In the final analysis, anorgasmy is psychological in origin; few, if any, females lack the neurophysiology necessary for orgasm, and anthropology shows that in sexually permissive societies virtually all females have little difficulty in attaining orgasm in coitus.

Anorgasmy is treated by removing inhibitions (inhibition), by teaching coital techniques, and by inducing orgasm through noncoital methods. The effective therapist should also impress upon the female that not reaching orgasm is no sign of failure or inadequacy on her part or her partner's and that sexual activity is very pleasurable to both, even if orgasm does not ensue. Indeed, some females derive great pleasure and satisfaction without orgasm, a fact that should be made known to anxious male partners. Too great a concern over orgasm defeats itself. As Kinsey once pointed out, thinking is the enemy of sexual pleasure, and a female can scarcely have orgasm if she is worrying about whether she will attain it or not and if she senses that her partner is mentally turning the pages of a marriage manual.

Lastly, sexual problems are often perpetuated by the inability of the partners to communicate freely their feelings to one another. There is a curious and unfortunate reticence about informing one's partner as to what does or does not contribute to one's pleasure. The partner must function on a trial-and-error basis, ever on the alert for signs indicating the efficacy of his or her efforts. This muteness is even more pronounced when it comes to an individual making suggestions to the partner. Many persons feel that a suggestion or request would be interpreted by the partner that he or she had been inept or at least remiss. As with any other problems, sexual problems can be overcome or ameliorated only if the individuals concerned communicate effectively.

Social and cultural aspects

The effects of societal value systems on human sexuality are, as has already been mentioned, profound. The American anthropologist George P. Murdock (Murdock, George P.) summarized the situation, saying:

All societies have faced the problem of reconciling the need of controlling sex with that of giving it adequate expression, and all have solved it by some combination of cultural taboos, permissions, and injunctions. Prohibitory regulations curb the socially more disruptive forms of sexual competition. Permissive regulations allow at least the minimum impulse gratification required for individual well-being. Very commonly, moreover, sex behavior is specifically enjoined by obligatory regulations where it appears directly to subserve the interests of society.

The historical heritage is, of course, the foundation upon which the current situation rests. Western civilizations are basically Greco-Roman in social organization, philosophy, and law, with a powerful admixture of Judaism and Christianity. This historical mixture contained incompatible elements: individual freedom was cherished, yet there was a great emphasis on law and proper procedure; the pantheism of the Greeks and Romans clashed with Judeo-Christian monotheism; and the sexual permissiveness of Hellenistic times was answered by the antisexuality of early Christianity.

In terms of sex, the most important factor was Christianity. While other vital aspects of human life, such as government, property rights, kinship, and economics, were influenced to varying degrees, sexuality was singled out as falling almost entirely within the domain of religion. This development arose from an ascetic concept shared by a number of religions, the concept of the good spiritual world as opposed to the carnal materialistic world, the struggle (dualism) between the spirit and the flesh. Since sex epitomizes the flesh, it was obviously the enemy of the spirit. Beginning in the 2nd century, Western Christianity was heavily influenced by this dichotomous philosophy of the Gnostics; sex in any form outside of marriage was an unmitigated evil and, within marriage, an unfortunate necessity for purposes of procreation rather than pleasure. The powerful antisexuality of the early Christians (note that neither God nor Christ has a wife and that marriage does not exist in heaven) was in part due to their apocalyptic vision of life: they anticipated that the end of the world and the Last Judgment would soon be upon them. There was no time for a gradual weaning away from the flesh; an immediate and drastic approach was necessary. Indeed, such excessive antisexuality developed that the church itself was finally moved to curb some of its more extreme forms.

As it became evident that human existence was going to continue for some unforeseeable length of time and as occasional intelligent theologians made themselves felt, antisexuality was ameliorated to some extent but still remained a foundation stone of Christianity for centuries. This attitude was particularly unfortunate for women, to whom most of the sexual guilt was assigned. Women, like the original temptress Eve, continued to attract men to commit sin. They were spiritually weak creatures prone to yield to carnal impulses. This is, of course, a classic example of projecting one's own guilty desires upon someone else.

Ultimately, legal control over sexual behaviour passed from the church to the state, but in most instances the latter simply perpetuated the attitudes of the former. Priests and clergymen frequently continued to exert powerful extralegal control: denunciations from the pulpit can be as effective as statute law in some cases. Although religion has weakened as a social control mechanism, even today liberalization of sex laws and relaxation of censorship have often been successfully opposed by religious leaders. On the whole, however, Christianity has become progressively more permissive, and sexuality has come to be viewed not as sin but as a God-given capacity to be used constructively.

Apart from religion, the state sometimes imposes restrictions for purely secular reasons. The more totalitarian (totalitarianism) a government, the more likely it is to restrict or direct sexual behaviour. In some instances, this comes about simply as the consequence of a powerful individual (or individuals) being in a position to impose ideas upon the public. In other instances, one cannot escape the impression that sex, being a highly personal and individualistic matter, is recognized as antithetical to the whole idea of strict governmental control and supervision of the individual. This may help explain the rigid censorship exerted by most totalitarian regimes over sexual expression. It is as though such a government, being obsessed with power, cannot tolerate the power the sexual impulse exerts on the population.

Social control of sexual behaviour

Societies differ remarkably in what they consider socially desirable and undesirable in terms of sexual behaviour and consequently differ in what they attempt to prevent or promote. There appear, however, to be four basic sexual controls in the majority of human societies. First, to control endless competition, some form of marriage is necessary. This not only removes both partners from the competitive arena of courtship and assures each of a sexual partner, but it allows them to devote more time and energy to other necessary and useful tasks of life. Despite the beliefs of earlier writers, marriage (monogamy) is not necessary for the care of the young; this can be accomplished in other ways.

Second, control of forced sexual relationships is necessary to prevent anger, feuding, and other disruptive retribution.

Third, all societies exert control over whom one is eligible to marry or have as a sexual partner. endogamy, holding the choice within one's group, increases group solidarity but tends to isolate the group and limit its political strength. exogamy, forcing the individual to marry outside the group, dilutes group loyalty but increases group size and power through new external liaisons. Some combination of endogamy and exogamy is found in most societies. All have incest prohibitions. These are not based on genetic knowledge. Indeed, many incest taboos involve persons not genetically related (father–stepdaughter, for example). The prime reason for incest prohibition seems to be the necessity for preventing society from becoming snarled in its own web: every person has a complex set of duties, rights, obligations, and statuses with regard to other people, and these would become intolerably complicated or even contradictory if incest were freely permitted.

Fourth, there is control through the establishment of some safety-valve system: the formulation of exceptions to the prevailing sexual restrictions. There is the recognition that humans cannot perpetually conform to the social code and that well-defined exceptions must be made. There are three sorts of exceptions to sexual restrictions: (1) Divorce: while all societies encourage marriage, all realize that it is in the interest of society and the individual to terminate marriage under certain conditions. (2) Exceptions based on kinship: many societies permit or encourage sexual activity with certain kin, even after marriage. Most often these kin are a brother's wife or a wife's sister. In addition, sexual “joking relationships” are often expected between brothers-in-law, sisters-in-law, and cousins. While coitus is not involved, there is much explicit sexual banter, teasing, and humorous insult. (3) Exceptions based on special occasions, ranging from sexual activity as a part of religious rites (ritual) to purely secular ceremonies and celebrations wherein the customary sexual restrictions are temporarily lifted.

Turning to particular forms of sexual behaviour, one learns from anthropology and history that extreme diversity in social attitude is common. Most societies (primitive culture) are unconcerned over self-masturbation since it does not entail procreation or the establishment of social bonds, but a few regard it with disapprobation. Sexual dreams cause concern only if they are thought to be the result of the nocturnal visitation of some spirit. Such dreams were once attributed to spirits or demons known as incubi (incubus) and succubi (succubus), who sought out sleeping humans for sexual intercourse.

Petting among most preliterate societies is done only as a prelude to coitus—as foreplay—rather than as an end in itself. In some parts of sub-Saharan Africa, however, petting is used as a premarital substitute for coitus in order to preserve virginity and avoid pregnancy. There is great variation in petting and foreplay techniques. Kissing is by no means universal, as some groups view the mouth as a biting and chewing orifice ill-suited for expressing affection. While some societies emphasize the erotic role of the female breast, others—such as the Chinese (China)—pay little attention to it. Still others regard oral stimulation of the breast unseemly, being too akin to infantile suckling. Although manual stimulation of the genitalia is nearly universal, a few peoples abstain because of revulsion toward genital secretions. Not much information exists on mouth–genital contact, and one can say only that it is common among some peoples and rare among others.

A considerable number of societies manifest scratching and biting in conjunction with sexual (sadism) activity, and most of this is done by the female. Sadomasochism (masochism) in any other form, however, is conspicuous by its absence in preliterate societies.

An enumeration of the societies that permit or forbid premarital coitus is complicated not only by the double standard but also by the fact that such prohibition or permission is often qualified. As a rough estimate, however, 40 to 50 percent of preliterate or ancient societies allowed premarital coitus under certain conditions to both males and females. If one were to count as permissive those groups that theoretically disapprove but actually condone such coitus, the percentage would rise to perhaps 70.

In marital coitus, when sexual access is not only permitted but encouraged, one would expect considerable uniformity in frequency of coitus. This expectation is not fulfilled: social conditioning profoundly affects even marital coitus. On one Irish island reported upon by a researcher, for example, marital coitus is best measured in terms of per year, and among the Cayapas (Chachi) of Ecuador, a frequency of twice a week is something to boast of. The coital frequencies of other groups, on the other hand, are nearer to human potential. In one Polynesian group, the usual frequency of marital coitus among individuals in their late 20s was 10 to 12 per week, and in their late 40s the frequency had fallen to three to four. The African Bala, according to one researcher, had coitus on the average of once or twice per day from young adulthood into the sixth decade of life.

Marital coitus is not unrestricted. Coitus during menstruation or after a certain stage of pregnancy is generally taboo. After childbirth a lengthy period of time must often elapse before coitus can resume, and some peoples abstain for magical reasons before or during warfare, hunting expeditions, and certain other important events or ceremonies. In modern Western society one finds menstrual, pregnancy, and postpartum taboos (taboo) perpetuated under an aesthetic or medical guise, and coaches still attempt to force celibacy upon athletes prior to competition.

Extramarital coitus (adultery) provides a striking example of the double standard: it is expected, or tolerated, in males and generally prohibited for females. Very few societies allow wives sexual freedom. Extramarital coitus with the husband's consent, however, is another matter. Somewhere between two-fifths and three-fifths of preliterate societies permit wife lending or allow the wife to have coitus with certain relatives (generally brothers-in-law) or permit her freedom on special ceremonial occasions. The main concern of preliterate societies is not one of morality, but of more practical considerations: does the act weaken kinship ties and loyalty? Will it damage the husband's social prestige? Will it cause pregnancy and complicate inheritance or cause the wife to neglect her duties and obligations? Most foreign of all to Western thinking is that of those peoples whose marriage ceremony involves the bride having coitus with someone other than the groom, yet it is to be recalled that this practice existed to a limited extent in medieval Europe as jus primae noctis (seigneur, droit du), the right of the lord to the bride of one of his subjects.

Sexual deviations and sex offenses are, of course, social definitions rather than natural phenomena. What is normative behaviour in one society may be a deviation or crime in another. One can go through the literature and discover that virtually any sexual act, even child–adult relations or necrophilia, has somewhere at some time been acceptable behaviour. Homosexuality is permitted in perhaps two-thirds of human societies. In some groups it is normative behaviour, whereas in others it is not only absent but beyond imagination. Generally, it is not an activity involving most of the population but exists as an alternative way of life for certain individuals. These special individuals are sometimes transvestites (transvestism)—that is, they dress and behave like the opposite sex. Sometimes they are regarded as curiosities or ridiculed, but more often they are accorded respect and magical powers are attributed to them. It is noteworthy, however, that aside from these transvestites, exclusive homosexuality is quite rare in preliterate societies.

In conclusion, the cardinal lesson of anthropology is that no type of sexual behaviour or attitude has a universal, inherent social or psychological value for good or evil—the whole meaning and value of any expression of sexuality is determined by the social (social class) context within which it occurs.

Class distinctions

Differences in sexual behaviour between classes within technologically developed societies are very marked. Civilizations are made up of class hierarchies, and the different subgroups normally develop their own value systems. Most of the knowledge of the sexual behaviour and attitudes of ancient cultures is that of the upper or ruling class; the behaviour and feelings of the slaves and peasants were seldom recorded. There is the impression—probably a correct one—that throughout history the lower socio-economic class was the most permissive. Sex has always been one of the few pleasures of the poor and oppressed. On the other hand, one must not overlook the fact that a fanatical Puritanism can also flourish at the bottom of the social scale, and, hence, one can never assume that low status and sexual permissiveness are inevitably linked.

The Kinsey (Kinsey, Alfred Charles) studies showed considerable social class differences in sexuality in the United States, chiefly in that the lower class was more tolerant of nonmarital coitus. More recent studies indicate that these class differences have rapidly broken down. Increased literacy and the influence of mass media have made the population more homogeneous in sexual attitudes. One can find, moreover, reversals of the previous pattern: a lower class person on the way up the social ladder may be quite conservative in his sexual views, feeling that this facilitates upward mobility, whereas the person secure in his or her high social status often feels that he or she can afford to flout convention. Actually, the most sexually liberal are those at the very bottom, who have nothing to lose, and those at the very top, who are beyond social retribution.

The great middle class remains the bastion of traditionalism, and it is here that the double standard of morality is most prominent. The intellectualized liberalism of the upper level seeps down only slowly, and the pragmatic egalitarianism of the lower level does not penetrate far upward.

Economic influences

Systems of production and distribution have had a growing influence on sexual behaviour since the Industrial Revolution. The old family pattern was inexorably disrupted by the rise of the industrial state. Children were no longer kept at home to share in the work and be economic assets but left for school or for nonfamily employment, and the degree of parental control diminished. The “working wife” employed outside the home, once found only among the impoverished, has gradually become the typical wife. With her enhanced economic power and her greater association with people outside the home, she became less a chattel. As the population left the family farm and tight-knit small communities for anonymous big-city existence, not only parental but societal controls over behaviour were weakened. Society became increasingly nomadic with improved transportation and job opportunities. Cultural and ethnic subgroups that formerly would have had little contact were thrown together in the same schools, factories, offices, and neighbourhoods.

All of this vast uprooting and rearranging naturally altered sexual attitudes and behaviour. The individual no longer had the option of choosing to conform or depart from a rather clear-cut sexual moral code but instead was faced with a multiplicity of choices of varying degrees of social acceptability. The major sexual change—one still in progress—was the emancipation of women, which brought with it an increasing acceptance of premarital sexual activity, the concept of woman as a human being with her own sexual needs and rights, and the possibility of terminating an unhappy marriage without incurring serious social censure. A second major change was the erosion of simplistic value systems: with increased mobility and social mixing, the individual learned that the values and attitudes he or she had unquestioningly accepted were not necessarily shared by neighbours and co-workers. As a result, life became not only more complex but more permissive. This growing tolerance has in recent decades extended, to a limited extent, to homosexuality. There is no evidence that homosexuality or other deviant behaviour has measurably increased as a result of society's urbanization and technological progress, but one gains the impression of an increase simply because these topics, previously unmentionable, are now openly discussed in the mass media.

While the old monolithic value systems broke down and individuals were accorded a wider variety of choices in terms of sexual life, there developed a paradoxical trend toward homogeneity as a result of mobility, the mass media, and increasing economic parity. Geographical and social-class differences in sexual attitudes and behaviour have steadily lessened. The plumber's family and the banker's family are now indistinguishable in terms of dress; both have automobiles; their offspring attend the same schools; and they share the same newspapers, magazines, and television programs. One might summarize by saying that society is homogeneous in that everyone now has available a wide diversity of sexual attitudes and activities.

Legal regulation

Sex laws, the origins of which, as mentioned above, are found within the church, are unique in one important respect. Whereas all other laws are basically concerned with the protection of person or property, the majority of sex laws are concerned solely with maintaining morality. The issue of morality is minimal in other laws: one can legitimately evict an impoverished old couple from their mortgaged home or sentence a hungry man for stealing food. Only in the realm of sex is there a consistent body of law upholding morality.

The earliest sex laws of which there is knowledge are from the Near East and date back to the 2nd millennium BC. They are remarkable in three respects: there are great omissions—certain acts are not mentioned whereas others receive detailed attention; some laws seem almost contradictory; and penalties are often extraordinarily severe. One obtains the distinct impression that these laws were case law—that is, laws formulated upon specific cases as they arose rather than being the result of lengthy judicial deliberation done in advance. These laws influenced Judaic and, hence, Christian thinking, and some were immortalized in the Bible, chiefly in Leviticus.

As mentioned earlier, when secular law replaced religious law, there was rather little change in content. In Europe the Napoleonic Code represented a break with tradition and introduced some measure of sexual tolerance, but in England and the United States there was no such rift with the past. In the latter country, as each new state joined the union, its sex laws simply duplicated, to a great extent, those of pre-existing states; legislators were disinclined to debate sexual issues or to risk losing votes by discarding or weakening sex laws.

Sex laws may be grouped in three categories: (1) Those concerned with protection of person. These are based on the element of consent. These otherwise logical laws become problematic when society deems that minors, mental retardates, and the insane are incapable of giving consent—hence, coitus with them is rape. (2) Those concerned with preventing offense to public sensibilities. Statutes preclude public sexual activity, exhibitionism, and offensive solicitation. (3) Those concerned with maintaining sexual morality. These constitute the majority of sex laws, covering such items as premarital coitus, extramarital coitus, incest, homosexuality, prostitution, peeping, nudity, animal contact, transvestism, censorship, and even specific sexual techniques—chiefly oral or anal. Laws relating to sexual conduct and morality are generally far more extensive in the United States than in western Europe and most other areas of the world.

In recent years, in Europe and the United States, a number of highly respected legal, medical, and religious organizations have deliberated on the issue of the legal control of human sexuality. They have been unanimous in the conclusion that, while laws protecting person and public sensibilities should be retained, the purely moral laws should be dropped. What consenting adults do in private, it is argued, should not be subject to legal control.

In the final analysis, sexuality, like any other vital aspect of human life, must be dealt with on an individual or societal level with a combination of rationality, sensitivity, and tolerance if society is to avoid personal and social problems arising from ignorance and misconception.

Paul Henry Gebhard Ed.

Sexually (sexually transmitted disease) transmitted diseases

Infections transmitted primarily by sexual contact are referred to as sexually transmitted diseases (STDs). Caused by a variety of microbial agents that thrive in warm, moist environments such as the mucous membranes of the vagina, urethra, anus, and mouth, STDs are diagnosed most frequently in individuals who engage in sexual activity with many partners.

In the past, a disease transmitted sexually was more commonly called a venereal disease, or VD, and was applied to only a few infections such as gonorrhea and syphilis. Actually more than 20 STDs have been identified, and infections caused by Chlamydia trachomatis, herpes simplex virus, and human papillomavirus, although underreported, are believed to be more prevalent than gonorrhea in the United States. Although the incidence of some STDs has reached epidemic proportions, it was not until the advent of the acquired immunodeficiency syndrome (AIDS) that the need to restrain the transmission of these diseases gained serious attention.

AIDS is a deadly disease for which there is no known cure. This fact has made prevention of the spread of HIV (see below) infection a top priority of the health-care community, with education concerning safer sexual practices at the fore. The “safe sex” strategy, which includes encouraging the use of condoms or the practice of abstinence, has been introduced to prevent the spread not only of AIDS but of all STDs. Stemming the transmission of disease rather than relying on treatment, which in the case of AIDS does not even exist, is the basic tenet of the safe-sex doctrine.

Preventing the transmission of STDs is also important because many of these diseases do not produce initial symptoms of any significance. Thus, they often go untreated, increasing their spread and the incidence of serious complications; untreated chlamydial infections in women are the primary preventable cause of female sterility.

Common sexually transmitted organisms

Bacteria, parasites, and viruses are the most common microbial agents involved in the sexual transmission of disease. Bacterial agents include Neisseria gonorrhoeae, which causes gonorrhea and predominantly involves the ureter in men and the cervix in women, and Treponema pallidum, which is responsible for syphilis. The parasite Chlamydia trachomatis causes a variety of disorders—in women, urethritis, cervicitis, and salpingitis (inflammation of the ureter, cervix, and fallopian tubes, respectively) and, in men, nongonococcal urethritis. Sexually transmitted viral agents include the human papillomavirus (human papillomavirus), which causes genital warts. Infection by this virus, of which there are more than 20 types, has been linked to cervical carcinoma. herpes simplex virus II is the causative agent of genital herpes, a condition in which ulcerative blisters form on the mucous membranes of the genitalia.

Acquired immunodeficiency syndrome (AIDS)

AIDS is caused by the human immunodeficiency virus (HIV), a pernicious infectious agent that attacks the immune system, leading to its progressive destruction. The virus is found in highest concentrations in the blood, semen, and vaginal and cervical fluids of the human body and can be harboured asymptomatically for 10 years or more. Although the primary route of transmission is sexual, HIV also is spread by the use of infected needles among intravenous drug users, by the exchange of infected blood products, and from an infected mother to her fetus during pregnancy.

The progression of the syndrome does not follow a defined path; instead nonspecific symptoms reflect the myriad effects of a failing immune system. These symptoms are referred to as AIDS-related complex (ARC) and include fever, rashes, weight loss, and wasting. Opportunistic infections such as Pneumocystis carinii pneumonia, neoplasms such as Kaposi's sarcoma, and central nervous system dysfunction are also common complications. The patient eventually dies, unable to mount an immunologic defense against the constant onslaught of infections.

A blood test can be used to detect HIV infection before the symptoms begin to manifest themselves, and all individuals who may be at even the slightest risk of infection are encouraged to be tested in order to prevent the unknowing spread of HIV to others. Identification of infection before the onset of the disease, however, does not promise a better prognosis; the vast majority of those infected with HIV will ultimately succumb to AIDS. Although development of a vaccine is being pursued, it is not yet available and education remains the best way to prevent transmission of this lethal disease.

Ed.

Additional Reading

General information may be found in Benjamin B. Wolman and John Money (eds.), Handbook of Human Sexuality (1980, reissued 1993); James Leslie McCary and Stephen P. McCary, McCary's Human Sexuality, 4th ed. (1982); Zira DeFries, Richard C. Friedman, and Ruth Corn (eds.), Sexuality: New Perspectives (1985), a compilation of recent interdisciplinary research; Herant A. Katchadourian, Fundamentals of Human Sexuality, 5th ed. (1989); June M. Reinisch and Ruth Beasley, The Kinsey Institute New Report on Sex: What You Must Know to Be Sexually Literate (1990), a summary of current thinking in sex research; William H. Masters, Virginia E. Johnson, and Robert C. Kolodny, Human Sexuality, 4th ed. (1992); and Janet Shibley Hyde, Understanding Human Sexuality, 5th ed. (1994). A popular treatment of various aspects of sex is found in Stefan Bechtel et al., The Practical Encyclopedia of Sex and Health (also published as The Sex Encyclopedia, 1993). Reference works on human sexuality include Robert T. Francoeur, Timothy Perper, and Norman A. Scherzer (eds.), A Descriptive Dictionary and Atlas of Sexology (1991); Michael A. Carrera, The Language of Sex: An A to Z Guide (1992); and two annotated bibliographies, Mervyn L. Mason, Human Sexuality: A Bibliography and Critical Evaluation of Recent Texts (1983); and Suzanne G. Frayser and Thomas J. Whitby, Studies in Human Sexuality: A Selected Guide (1987).The history of the study of human sexuality is chronicled in Paul Robinson, The Modernization of Sex: Havelock Ellis, Alfred Kinsey, William Masters, and Virginia Johnson (1976); Vern L. Bullough, Sexual Variance in Society and History (1976); Jeffrey Weeks, Sexuality and Its Discontents: Meanings, Myths & Modern Sexualities (1985), and Sex, Politics, and Society: The Regulation of Sexuality Since 1800, 2nd ed. (1989), the latter focusing on Great Britain; Pat Caplan (ed.), The Cultural Construction of Sexuality (1987); John D'Emilio and Estelle B. Freedman, Intimate Matters: A History of Sexuality in America (1988); Sander L. Gilman, Sexuality: An Illustrated History: Representing the Sexual in Medicine and Culture from the Middle Ages to the Age of AIDS (1989); and Janice M. Irvine, Disorders of Desire: Sex and Gender in Modern American Sexology (1990).Significant studies of specifically female or male sexuality in the United States are Alfred C. Kinsey, Wardell B. Pomeroy, and Clyde E. Martin, Sexual Behavior in the Human Male (1948); Alfred C. Kinsey et al., Sexual Behavior in the Human Female (1953, reissued 1973); and Shere Hite, The Hite Report: A Nationwide Study on Female Sexuality, new rev. ed. (1981), and The Hite Report on Male Sexuality (1981), although criticism has been leveled at the studies' methodology.Anthropological overviews of sex are given in Donald S. Marshall and Robert C. Suggs (eds.), Human Sexual Behavior: Variations in the Ethnographic Spectrum (1971); George P. Murdock, Social Structure (1949, reissued 1965); and Clellan S. Ford and Frank A. Beach, Patterns of Sexual Behavior (1951, reprinted 1980), which compares sexual behaviour patterns of nearly 200 human cultural groups worldwide and of a large number of related mammals.Sexual physiology is comprehensively treated in William H. Masters and Virginia E. Johnson, Human Sexual Response (1966, reissued 1986); Loretta P. Higgins and Joellen W. Hawkins, Human Sexuality Across the Life Span (1984), a text for nursing practice; and Simon LeVay, The Sexual Brain (1993), which includes a discussion of the author's report of the size variation of a part of the hypothalamus with respect to sexual orientation among men. William H. Masters and Virginia E. Johnson, Human Sexual Inadequacy (1970, reissued 1980), reports behaviour therapy treatments of sexual dysfunction. Richard Green and John Money (eds.), Transsexualism and Sex Reassignment (1969), discusses sex change. John Money, Gay, Straight, and In-Between: The Sexology of Erotic Orientation (1988), analyzes determining physiological, cultural, and personal history factors.The psychological differences between the sexes and the relationship of gender are analyzed by Robert J. Stoller, Sex and Gender, 2 vol. (1968–75); Eleanor Emmons Maccoby and Carol Nagy Jacklin, The Psychology of Sex Differences (1974); G. Mitchell, Human Sex Differences (1981), a primatologist's investigation; John Archer and Barbara Lloyd, Sex and Gender (1982), also published in an enlarged, revised North American edition with the same title (1985); and June M. Reinisch, Leonard A. Rosenblum, and Stephanie A. Sanders (eds.), Masculinity/Femininity: Basic Perspectives (1987). Biological data is examined by Anne Fausto-Sterling, Myths of Gender: Biological Theories About Women and Men, 2nd ed. (1992).Social and cultural aspects of human sexuality are investigated by Louis M. Epstein, Sex Laws and Customs in Judaism (1948, reissued 1968), a detailed history of Judeo-Christian attitudes toward sex; Derrick S. Bailey, Sexual Relation in Christian Thought (also published as The Man-Woman Relationship in Christian Thought, 1959); Ira L. Reiss, The Social Context of Premarital Sexual Permissiveness (1967), and Journey into Sexuality (1986), a study of the relationship between cross-cultural differences in nonsexual and sexual patterns; Robert Coles and Geoffrey Stokes, Sex and the American Teenager (1985); and Arthur S. Leonard, Sexuality and the Law: An Encyclopedia of Major Legal Cases (1993), restricted, however, to United States law.Diseases transmitted through sexual contact are described in Allan M. Brandt, No Magic Bullet: A Social History of Venereal Disease in the United States Since 1880 (1985); Charles E. Rinear, The Sexually Transmitted Diseases (1986); and L.C. Parish and Friedrich Gschnait (eds.), Sexually Transmitted Diseases: A Guide for Clinicians (1989).

词条	sexual behaviour, human
释义	sexual behaviour, human Introduction any activity—solitary, between two persons, or in a group—that induces sexual arousal. There are two major determinants of human sexual behaviour: the inherited sexual response patterns that have evolved as a means of ensuring reproduction and that are a part of each individual's genetic inheritance, and the degree of restraint or other types of influence exerted on the individual by society in the expression of his sexuality. The objective here is to describe and explain both sets of factors and their interaction. It should be noted that taboos in Western culture and the immaturity of the social sciences for a long time impeded research concerning human sexual behaviour, so that by the early 20th century scientific knowledge was largely restricted to individual case histories that had been studied by such European writers as Sigmund Freud, Havelock Ellis, and Richard, freiherr von Krafft-Ebing. By the 1920s, however, the foundations had been laid for the more extensive statistical studies that were conducted before World War II in the United States. Of the two major organizations for sex study, one, the Institut für Sexualwissenschaft in Berlin (established in 1897), was destroyed by the Nazis in 1933. The other, the Institute for Sex Research (later renamed Kinsey Institute for Research in Sex, Gender, and Reproduction), begun in 1938 by the American sexologist Alfred Charles Kinsey (Kinsey, Alfred Charles) at Indiana University in Bloomington, undertook the study of human sexual behaviour. Much of the following discussion rests on the findings of the Institute for Sex Research, which comprise the most comprehensive data available. The only other country for which comprehensive data exist is Sweden. Types of behaviour Human sexual behaviour may conveniently be classified according to the number and gender of the participants. There is solitary behaviour involving only one individual, and there is sociosexual behaviour involving more than one person. Sociosexual behaviour is generally divided into heterosexual behaviour (male with female) and homosexual behaviour (male with male or female with female). If three or more individuals are involved it is, of course, possible to have heterosexual and homosexual activity simultaneously. In both solitary and sociosexual behaviour there may be activities that are sufficiently unusual to warrant the label deviant behaviour. The term deviant should not be used as a moral judgment but simply as indicating that such activity is not common in a particular society. Since human societies differ in their sexual practices, what is deviant in one society may be normal in another. Solitary behaviour Self-masturbation is self-stimulation with the intention of causing sexual arousal and, generally, orgasm (sexual climax). Most masturbation is done in private as an end in itself but is sometimes practiced to facilitate a sociosexual relationship. Masturbation, generally beginning at or before puberty, is very common among males, particularly young males, but becomes less frequent or is abandoned when sociosexual activity is available. Consequently, masturbation is most frequent among the unmarried. Fewer females masturbate; in the United States, roughly one-half to two-thirds have done so, as compared to nine out of ten males. Females also tend to reduce or discontinue masturbation when they develop sociosexual relationships. There is great individual variation in frequency, so that it is impractical to try to define what range could be considered “normal.” The myth persists, despite scientific proof to the contrary, that masturbation is physically harmful. Neither is there evidence that masturbation is immature behaviour; it is common among adults deprived of sociosexual opportunities. While solitary masturbation does provide pleasure and relief from the tension of sexual excitement, it does not have the same psychological gratification that interaction with another person provides; thus, extremely few people prefer masturbation to sociosexual activity. The psychological significance of masturbation lies in how the individual regards it. For some, it is laden with guilt; for others, it is a release from tension with no emotional content; and for others it is simply another source of pleasure to be enjoyed for its own sake. The majority of males and females have fantasies of some sociosexual activity while they masturbate. The fantasy not infrequently involves idealized sexual partners and activities that the individual has not experienced and even might avoid in real life. Since the masturbating person is in sole control of the areas that are stimulated, the degree of pressure, and the rapidity of movement, masturbation is often more effective in producing sexual arousal and orgasm than is sociosexual activity, during which the stimulation is determined to some degree by one's partner. Orgasm in sleep evidently occurs only in humans. Its causes are not wholly known. The idea that it results from the pressure of accumulated semen is invalid because not only do nocturnal emissions sometimes occur in males on successive nights, but females experience orgasm in sleep as well. In some cases orgasm in sleep seems a compensatory phenomenon, occurring during times when the individual has been deprived of or abstains from other sexual activity. In other cases it may result from external stimuli, such as sleeping prone or having night clothing caught between one's legs. Most orgasms during sleep are accompanied by erotic dreams. A great majority of males experience orgasm in sleep. This almost always begins and is most frequent in adolescence, tending to disappear later in life. Fewer females have orgasm in sleep, and, unlike males, they usually begin having such experience when fully adult. Orgasm in sleep is generally infrequent, seldom exceeding a dozen times per year for males and three or four times a year for the average female. Most sexual arousal does not lead to sexual activity with another individual. Humans are constantly exposed to sexual stimuli when seeing attractive persons and are subjected to sexual themes in advertising and the mass media. Response to such visual and other stimuli is strongest in adolescence and early adult life and usually gradually declines with advancing age. One of the necessary tasks of growing up is learning to cope with one's sexual arousal and to achieve some balance between suppression, which can be injurious, and free expression, which can lead to social difficulties. There is great variation among individuals in the strength of sex drive and responsiveness, so this necessary exercise of restraint is correspondingly difficult or easy. Sociosexual behaviour By far the greatest amount of sociosexual behaviour is heterosexual behaviour between only one male and one female. Heterosexual behaviour frequently begins in childhood, and, while much of it may be motivated by curiosity, such as showing or examining genitalia, many children engage in sex play because it is pleasurable. The sexual impulse and responsiveness are present in varying degrees in most children and latent in the remainder. With adolescence, sex play is superseded by dating, which is socially encouraged, and dating almost inevitably involves some physical contact resulting in sexual arousal. This contact, labelled necking or petting, is a part of the learning process and ultimately of courtship and the selection of a marriage partner. Petting varies from hugging, kissing, and generalized caresses of the clothed body to techniques involving genital stimulation. Petting may be done for its own sake as an expression of affection and a source of pleasure, and it may occur as a preliminary to coitus. This last form of petting is known as foreplay. In a minority of cases, but a substantial minority, petting leads to orgasm and may be a substitute for coitus. Excluding foreplay, petting is usually very stereotyped, beginning with hugging and kissing and gradually escalating to stimulation of the breasts and genitalia. In most societies petting and its escalation are initiated by the male more often than by the female, who generally rejects or accepts the male's overtures but refrains from playing a more aggressive role. Petting in some form is a near-universal human experience and is valuable not only in mate selection but as a means of learning how to interact with another person sexually. Coitus (sexual intercourse), the insertion of the penis into the vagina, is viewed by society quite differently depending upon the marital status of the individuals. The majority of human societies permit premarital coitus, at least under certain circumstances. In more repressive societies, such as modern Western society, it is more likely to be tolerated (but not encouraged) if the individuals intend marriage. Marital coitus is usually regarded as an obligation in most societies. Extramarital coitus (adultery), particularly by wives, is generally condemned and, if permitted, is allowed only under exceptional conditions or with specified persons. Societies tend to be more lenient toward males than females regarding extramarital coitus. This double standard of morality is also seen in premarital life. Postmarital coitus (i.e., coitus by separated, divorced or widowed persons) is almost always ignored. Even societies that try to confine coitus to marriage recognize the difficulty of trying to force abstinence upon sexually experienced and usually older persons. In the United States and much of Europe, there has been, within the last century, a progressive trend toward an increase in premarital coitus. Currently in the United States, at least three-quarters of the males and over half of the females have experienced premarital coitus. The proportions for this experience vary in different groups and socioeconomic classes. In Scandinavia, the incidence of premarital coitus is far greater, exceeding the 90 percent mark in Sweden, where it is now expected behaviour. Extramarital coitus continues to be openly condemned but is becoming more tolerated secretly, particularly if mitigating circumstances are involved. In some areas, such as southern Europe and Latin America (Latin America, history of), extramarital coitus is expected of most husbands and is accepted by society if the behaviour is not too flagrant. The wives do not generally approve but are resigned to what they believe to be a masculine propensity. In the United States, where at least half the husbands and one-quarter of the wives have extramarital coitus at some point in their lives, there have recently developed small organizations or clubs that exist to provide extramarital coitus for married couples. Despite the publicity they have engendered, however, extremely few individuals have belonged to such organizations. Most extramarital coitus is done secretly without the knowledge of the spouse. Most husbands and wives feel very possessive of their spouses and interpret extramarital activity as an aspersion on their own sexual adequacy, as indicating a loss of affection and as being a source of social disgrace. Human beings are not inherently monogamous (monogamy) but have a natural desire for diversity in their sexuality as in other aspects of life. Some societies have provided a release for these desires by suspending the restraints on extramarital coitus on special occasions or with certain individuals, and in modern Western society a certain amount of extramarital flirtation or mild petting at parties is not considered unusual behaviour. Discussion of sociosexual behaviour would be incomplete without some note of the role it has played in ceremony and religion. While the major religions of today are to varying degrees antisexual, many religions have incorporated sexual behaviour into their rites (ritual) and ceremonies. Human beings' ancient and continuing interest in their own fertility and in that of food plants and animals makes such a connection between sex and religion inevitable, particularly among peoples with uncertain food supplies. In most religions the deities were considered to have active sexual lives and sometimes took a sexual interest in humans. In this regard it is noteworthy that in Christianity sexual behaviour is absent in heaven and sexual proclivities are ascribed only to evil supernatural beings: Satan, devils, incubi (incubus), and succubi (succubus) (spirits or demons who seek out sleeping humans for sexual intercourse). Whether or not a behaviour is interpreted by society or the individual as erotic (i.e., capable of engendering sexual response) depends chiefly on the context in which the behaviour occurs. A kiss, for example, may express asexual affection (as a kiss between relatives), respect (a French officer kissing a soldier after bestowing a medal on him), reverence (kissing the hand or foot of a pope), or it may be a casual salutation and social amenity. Even something as specific as touching genitalia is not construed as sexual if done for medical reasons. In other words, the apparent motivation of the behaviour determines its interpretation. Individuals are extremely sensitive in judging motivations: a greeting kiss, if protracted more than a second or two, takes on a sexual connotation, and recent studies show that if an adult male at a party stands closer than the length of his hand and forearm to a female, she generally imputes a sexual motive to his proximity. Nudity is construed as erotic or even as a sexual invitation—unless it occurs in a medical context, in a group consisting of but one gender, or in a nudist camp. Physiological aspects Sexual response Sexual response follows a pattern of sequential stages or phases when sexual activity is continued. First, there is the excitement phase marked by increase in pulse and blood pressure, an increase in blood supply to the surface of the body resulting in increased skin temperature, flushing, and swelling of all distensible body parts (particularly noticeable in the penis and female breasts), more rapid breathing, the secretion of genital fluids, vaginal expansion, and a general increase in muscle tension. These symptoms of arousal eventually increase to a near maximal physiological level, the plateau phase, which is generally of brief duration. If stimulation is continued, orgasm usually occurs. Orgasm is marked by a feeling of sudden intense pleasure, an abrupt increase in pulse rate and blood pressure, and spasms of the pelvic muscles causing vaginal contractions in the female and ejaculation by the male. Involuntary vocalization may also occur. Orgasm lasts for a few seconds (normally not over ten), after which the individual enters the resolution phase, the return to a normal or subnormal physiological state. Up to the resolution phase, males and females are the same in their response sequence, but, whereas males return to normal even if stimluation continues, continued stimulation can produce additional orgasms in females. In brief, after one orgasm a male becomes unresponsive to sexual stimulation and cannot begin to build up another excitement phase until some period of time has elapsed, but females are physically capable of repeated orgasms without the intervening “rest period” required by males. Genetic (genetics, human) and hormonal factors While all normal individuals are born with the neurophysiology necessary for the sexual-response cycle described above, inheritance determines the intensity of their responses and their basic “sex drive.” There is great variation in this regard: some persons have the need for frequent sexual expressions; others require very little; and some persons respond quickly and violently, while others are slower and milder in their reactions. While the genetic basis of these differences is unknown and while such variations are obscured by conditioning, there is no doubt that sexual capacities, like all other physiological capacities, are genetically determined. It is unlikely, however, that genes control the sexual orientation of normal humans in the sense of individuals being predestined to become homosexual or heterosexual. Some severe genetic abnormality can, of course, profoundly affect intelligence, sexual capacity, and physical appearance and hence the entire sexual life. While the normal female has 44 autosomes plus two X-chromosomes (female) and the normal male 44 autosomes plus one X-chromosome and one Y-chromosome (male), many genetic abnormalities are possible. There are females, for example, with too many X-chromosomes (44+XXX) or too few (44+X) and males with an extra female chromosome (44+XXY) or an extra male chromosome (44+XYY). No 44+YY males exist—an X-chromosome is necessary for survival, even in the womb. One's genetic makeup determines one's hormonal status and the sensitivity of one's body to these hormones. While a disorder of any part of the endocrine system (endocrine system, human) can adversely affect sexual life, the hormones most directly influencing sexuality are the androgens (androgen) (male sex hormones), produced chiefly in the testicles (testis), and the estrogens (estrogen) (female sex hormones), produced chiefly in the ovaries (ovary). In early embryonic life there are neither testicles nor ovaries but simply two undifferentiated organs (gonads (gonad)) that can develop either into testicles or ovaries. If the embryo has a Y-chromosome, the gonads become testicles; otherwise, they become ovaries. The testicles of the fetus produce androgens, and these cause the fetus to develop male anatomy. The absence of testicles results in the development of female anatomy. Animal experiments show that, if the testicles of a male fetus are removed, the individual will develop into what seems a female (although lacking ovaries). Consequently, it has been said that humans are basically female. After birth and until puberty, the ovaries and testicles produce comparatively few hormones, and little girls and boys are much alike in size and appearance. At puberty, however, these organs begin producing in greater abundance, with dramatic results. The androgens produced by boys cause changes in body build, greater muscular development, body and facial hair, and voice change. In girls the estrogens cause breast development, menstruation, and feminine body build. A boy castrated (castration) before puberty does not develop masculine physical characteristics and manifests in adult life more of a feminine body build, lack of masculine body and facial hair, less muscular strength, a high voice, and small genitalia. A girl who has her ovaries removed before puberty is less markedly altered but retains a childlike body build, does not develop breasts, and never menstruates. Castrated individuals or persons producing insufficient hormones can be restored to a normal condition by administration of appropriate hormones. Beyond their role in developing the secondary sexual characteristics of the body, the hormones continue to play a role in adult life. An androgen deficiency causes a decrease in a man's sexual responsiveness, and an estrogen deficiency adversely affects a woman's fertility and causes atrophy of the genitalia. A loss of energy may also result in both men and women. Androgen seems linked in both males and females with aggressiveness and strength of sexual drive. When androgen is given to a female in animal experiments, she becomes more aggressive and displays behaviour more typical of males—by mounting other animals, for example. Estrogen increases her sexual responsiveness and intensifies her female behaviour. Androgen given to a male often increases his sexual behaviour, but estrogen diminishes his sex drive. In humans the picture is more complex, since human sexual behaviour and response is less dependent on hormones once adulthood has been reached. Removing androgen from an adult male reduces his sexual capacity; but this occurs gradually, and sometimes the reduction is small. Giving androgen to a normal human male generally has little or no effect since he is already producing all he can use. Giving him estrogen reduces his sex drive. Administration of androgen to an adult human female often increases her sex drive, enlarges her clitoris, and promotes the growth of facial hair. Giving estrogen to a normal woman before menopausal age generally has no effect whatsoever—probably because human females, unlike other female mammals, do not have hormonally controlled periods of “heat” (estrus). Hormones have no connection with the sexual orientation of humans. Male homosexuals do not have more estrogens than normal males (who have a little) nor can their preferences be altered by giving them androgen. Nervous system (nervous system, human) factors The nervous system consists of the central nervous system and the peripheral nervous system. The brain and spinal cord constitute the central system, while the peripheral system is composed of (1) the cerebrospinal nerves that go to the spinal cord (afferent nerves), transmitting sensory stimuli and those that come from the cord (efferent nerves) transmitting impulses to activate muscles, and (2) the autonomic system (autonomic nervous system), the primary function of which is the regulation and maintenance of the body processes necessary to life, such as heart rate, breathing, digestion, and temperature control. Sexual response involves the entire nervous system. The autonomic system controls the involuntary responses; the afferent cerebrospinal nerves carry the sensory messages to the brain; the efferent cerebrospinal nerves carry commands from the brain to the muscles; and the spinal cord serves as a great transmission cable. The brain itself is the coordinating and controlling centre, interpreting what sensations are to be perceived as sexual and issuing appropriate “orders” to the rest of the nervous system. The parts of the brain thought to be most concerned with sexual response are the hypothalamus and the limbic system, but no specialized “sex centre” has been located in the human brain. Animal experiments indicate that each individual has coded in its brain two sexual response patterns, one for mounting (masculine) behaviour and one for mounted (feminine) behaviour. The mounting pattern can be elicited or intensified by male sex hormone and the mounted pattern by female sex hormone. Normally, one response pattern is dominant and the other latent but capable of being called into action when suitable circumstances occur. The degree to which such inherent patterning exists in humans is unknown. While the brain is normally in charge, there is some reflex (i.e., not brain-controlled) sexual response. Stimulation of the genital and perineal area can cause the “genital reflex”: erection and ejaculation in the male, vaginal changes and lubrication in the female. This reflex is mediated by the lower spinal cord, and the brain need not be involved. Of course, the brain can override and suppress such reflex activity—as it does when an individual decides that a sexual response is socially inappropriate. Development (biological development) and change in the reproductive system One's anatomy and sexuality change with age. The changes are rapid in intra-uterine life and around puberty but are much slower and gradual in other phases of the life cycle. The reproductive organs first develop in the same form for both males and females: internally there are two undifferentiated gonads and two pairs of parallel ducts (Wolffian (Wolffian duct) and Müllerian ducts); externally there is a genital protrusion with a groove (urethral groove) below it, the groove being flanked by two folds (urethral folds). On either side of the genital protrusion and groove are two ridgelike swellings (labioscrotal swellings). Around the fourth week of life the gonads differentiate into either testes or ovaries. If testes develop, the hormone they secrete causes the Müllerian duct to degenerate and almost vanish and causes the Wolffian duct to elaborate into the sperm-carrying tubes and related organs (the vas deferens, epididymis, and seminal vesicles, for example). If ovaries develop, the Wolffian duct deteriorates, and the Müllerian duct elaborates to form the fallopian tubes, uterus, and part of the vagina. The external genitalia simultaneously change. The genital protrusion becomes either a penis or clitoris. In the female the groove below the clitoris stays open to form the vulva, and the folds on either side of the groove become the inner lips of the vulva (the labia minora). In the male these folds grow together, converting the groove into the urethral tube of the penis. The ridgelike swellings on either side remain apart in the female and constitute the large labia (labia majora), but in the male they grow together to form the scrotal sac into which the testes subsequently descend. At birth both male and female have all the neurophysiological equipment necessary for sexual response, although the reproductive system is not at this stage functional. Sexual interests, sexual behaviour, and sexual response are seen with increasing frequency in most children from infancy on. Even newborn males have penile erections, and babies of both sexes seem to find pleasure in genital stimulation. What appears to be orgasm has been observed in infant boys and girls, and, later in childhood, orgasm definitely can occur in masturbation or sex play. puberty may be defined as that short period of time (generally two years) during which the reproductive system matures and the secondary sexual characteristics appear. The ovaries and testes begin producing much larger amounts of hormones, pubic hair appears, female breasts develop, the menstrual cycle begins in females, spermatozoa and viable eggs are produced, and males experience voice change and a sudden acceleration in growth. Puberty generally occurs in females around age 12–13 and in males at about 13–14, but there is much individual variation. With puberty there is generally an intensification or the first appearance of sexual interest. Puberty marks the beginning of adolescence. Adolescence, from a physical viewpoint, is that period between puberty and the attainment of one's maximum height. By the latter point, which occurs around age 16 in females and 18 in males, the individual has adult anatomy and physiology. In late adolescence the majority of individuals are probably at their peak in terms of sexual capacity: the ability to respond quickly and repeatedly. During this period the sex drive is at its maximum in males, although it is difficult to say whether this is also true of females, since female sexuality, in many societies, is frequently suppressed during adolescence. Following adolescence there are about three decades of adult life during which physiological changes are slow and gradual. While muscular strength increases for a time, the changes may best be described as slow deterioration. This physical decline is not immediately evident in sexual behaviour, which often increases in quantity and quality as the individual develops more social skills and higher socio-economic status and loses some of the inhibitions (inhibition) and uncertainties that often impede adolescent sexuality. Indeed, in the case of the United States female, the deterioration (human aging) is more than offset by her gradual loss of sexual inhibition, and the effect of age is not clear until menopausal symptoms begin. In the male, however, there is no such masking of deterioration, and the frequency of sexual activity and the intensity of interest and response slowly, but inexorably, decline. If one must arbitrarily select an age to mark the beginning of old age, 50 is appropriate. By then, most females have experienced menopausal symptoms, and most males have been forced to recognize their increasing physical limitations. With menopause, the female genitalia gradually begin to atrophy and the amount of vaginal secretion diminishes—this is the direct consequence of the cessation of ovarian function and can be prevented, or the symptoms reversed, by administering estrogen. If a female has had a good sexual adjustment prior to menopause and if she does not believe in the fallacy that it spells the end of sexual life, menopause will have no adverse effect on her sexual and orgasmic ability. There is reason to believe that if a woman remains in good health and genital atrophy is prevented, she could enjoy sexual activity regardless of age. Males in good health are also capable of continuing sexual activity, although with an ever-decreasing frequency, throughout old age. The male has more difficulty in achieving erection, cannot maintain erection as long, and must have longer and longer “rest periods” between sexual acts. The amount of ejaculate becomes less, but most old males are still fertile. The Cowper's gland (bulbourethral gland) secretion (called “precoital mucus”) diminishes or disappears entirely. According to Kinsey's data, about one-quarter of males are impotent (impotence) by age 65, one-half by age 75, and three-quarters by age 80. One must remember, however, that some unknown but certainly substantial proportion of this impotence may be attributed to poor health. In general, the female withstands the onslaughts of age better than the male. The reduction in the frequency of marital intercourse or even its abandonment is more often than not the result of male deterioration. Psychological aspects Effects of early conditioning Physiology sets only very broad limits on human sexuality; most of the enormous variation found among humans must be attributed to the psychological factors of learning and conditioning. The human infant (infancy) is born simply with the ability to respond sexually to tactile stimulation. It is only later and gradually that the individual learns or is conditioned to respond to other stimuli, to develop a sexual attraction to males or females or both, to interpret some stimuli as sexual and others as nonsexual, and to control in some measure his or her sexual response. In other words, the general and diffuse sexuality of the infant becomes increasingly elaborated, differentiated, and specific. The early years of life are, therefore, of paramount importance in the development of what ultimately becomes adult sexual orientation. There appears to be a reasonably fixed sequence of development. Before age five, the child develops a sense of gender identity, thinks of himself or herself as a boy or girl, and begins to relate to others differently according to their gender. Through experience the child learns what behaviour is rewarded and what is punished and what sorts of behaviour are expected of him or her. Parents, peers, and society (socialization) in general teach and condition the child about sex not so much by direct informational statements and admonitions as by indirect and often unconscious communication. The child soon learns, for example, that he can touch any part of his body or someone else's body except the anal–genital region. The child rubbing its genitals finds that this quickly attracts adult attention and admonishment or that adults will divert him or her from this activity. It becomes clear that there is something peculiar and taboo about this area of the body. This “genital taboo” is reinforced by the great concern over the child's excretory behaviour: bladder and bowel control is praised; loss of control is met by disappointment, chiding, and expressions of disgust. Obviously, the anal–genital area is not only a taboo area but a very important one as well. It is almost inevitable that the genitalia become associated with anxiety and shame. It is noteworthy that this attitude finds expression in the language of Western civilizations, as in “privates” (something to be kept hidden) and the German word for the genitals, Scham (“shame”). While all children in Western civilizations experience this antisexual teaching and conditioning, a few have, in addition, atypical sexual experiences, such as witnessing or hearing sexual intercourse or having sexual contact with an older person. The effects of such atypical experiences depend upon how the child interprets them and upon the reaction of adults if the experience comes to their attention. Seeing parental coitus is harmless if the child interprets it as playful wrestling but harmful if he considers it as hostile, assaultive behaviour. Similarly, an experience with an adult may seem merely a curious and pointless game, or it may be a hideous trauma leaving lifelong psychic scars. In many cases the reaction of parents and society determines the child's interpretation of the event. What would have been a trivial and soon-forgotten act becomes traumatic if the mother cries, the father rages, and the police interrogate the child. Some atypical developments occur through association during the formative years. A child may associate clothing, especially underclothing, stockings, and shoes with gender and sex and thereby establish the basis for later fetishism or transvestism. Others, having been spanked or otherwise punished for self-masturbation or childhood sex play, form an association between punishment, pain, and sex that could escalate later into sadism or masochism. It is not known why some children form such associations whereas others with apparently similar experience do not. Around the age of puberty, parents and society, who more often than not refuse to recognize that children have sexual responses and capabilities, finally face the inescapable reality and consequently begin inculcating children with their attitudes and standards regarding sex. This campaign by adults is almost wholly negative—the child is told what not to do. While dating (courtship) may be encouraged, no form of sexual activity is advocated or held up as model behaviour. The message usually is “be popular” (i.e., sexually attractive), but abstain from sexual activity. This antisexualism is particularly intense regarding young females and is reinforced by reference to pregnancy, venereal disease, and, most importantly, social disgrace. To this list religious (religion) families add the concept of the sinfulness of premarital sexual expression. With young males the double standard of morality still prevails. The youth receives a double message, “don't do it, but we expect that you will.” No such loophole in the prohibitions is offered young girls. Meanwhile, the young male's peer group is exerting a prosexual influence, and his social status is enhanced by his sexual exploits or by exaggerated reports thereof. As a result of this double standard of sexual morality, the relationship between young males and females often becomes a ritualized contest, the male attempting to escalate the sexual activity and the female resisting his efforts. Instead of mutuality and respect, one often has a struggle in which the female is viewed as a reluctant sexual object to be exploited, and the male is viewed as a seducer and aggressor who must succeed in order to maintain his self-image and his status with his peers. This sort of pathological relationship causes a lasting attitude on the part of females: men are not to be trusted; they are interested only in sex; a girl dare not smile or be friendly lest males interpret it as a sign of sexual availability, and so forth. Such an aura of suspicion, hostility, and anxiety is scarcely conducive to the development of warm, trusting relationships between males and females. Fortunately, love or infatuation usually overcomes this negativism with regard to particular males, but the average female still maintains a defensive and skeptical attitude toward men. Western society is replete with attitudes that impede the development of a healthy attitude toward sex. The free abandon so necessary to a full sexual relationship is, in the eyes of many, an unseemly loss of self-control, and self-control is something one is urged to maintain from infancy onward. Panting, sweating, and involuntary vocalization are incompatible with the image of dignity. Worse yet is any substance once it has left the body: it immediately becomes unclean. The male and female genital fluids are generally regarded with disgust—they are not only excretions but sexual excretions. Here again, societal concern over excretion is involved, for sexual organs are also urinary passages and are in close proximity to the “dirtiest” of all places—the anus. Lastly, many individuals in society regard menstrual (menstruation) fluid with disgust and abstain from sexual intercourse during the four to six days of flow. This attitude is formalized in Judaism, in which menstruating females are specifically labelled as ritually unclean. In view of all these factors working against a healthy, rational attitude toward sex and in view of the inevitable disappointments, exploitations, and rejections that are involved in human relationships, one might wonder how anyone could reach adulthood without being seriously maladjusted. The sexual impulse, however, is sufficiently strong and persistent and repeated sexual activity gradually erodes the inhibitions and any sense of guilt or shame. Further, all humans have a deep need to be esteemed, wanted, and loved. Sexual activity with another is seen as proof that one is attractive, desired, valued, and possibly loved—a proof very necessary to self-esteem and happiness. Hence, even among the very inhibited or those with weak sex drive, there is this powerful motivation to engage in sociosexual activity. Most persons ultimately achieve at least a tolerable sexual adjustment. Some unfortunates, nevertheless, remain permanently handicapped, and very few completely escape the effects of society's antisexual conditioning. While certain inhibitions and restraints are socially and psychologically useful—such as deferring gratification until circumstances are appropriate and modifying behaviour out of regard for the feelings of others—most people labour under an additional burden of useless and deleterious attitudes and restrictions. Sexual problems Sexual problems may be classified as physiological, psychological, and social in origin. Any given problem may involve all three categories; a physiological problem, for example, will produce psychological effects, and these may result in some social maladjustment. Physiological problems of a specifically sexual nature are rather few. Only a small minority of people suffer from diseases of or deficient development of the genitalia or that part of the neurophysiology governing sexual response. Many people, however, experience at some time sexual problems that are by-products of other pathologies or injuries. Vaginal infections, for example, retroverted uteri, prostatitis, adrenal tumours, diabetes, senile changes of the vagina, and cardiovascular conditions may cause disturbance of the sexual life. In brief, anything that seriously interferes with normal bodily functioning generally causes some degree of sexual trouble. Fortunately, the great majority of physiological sexual problems are solved through medication or surgery. Generally, only those problems involving damage to the nervous system defy therapy. Psychological (psychology) problems constitute by far the largest category. They are not only the product of socially induced inhibitions (inhibition), maladaptive attitudes, and ignorance but also of sexual myths held by society. An example of the latter is the idea that good, mature sex must involve rapid erection, protracted coitus, and simultaneous orgasm. Magazines, marriage books, and general sexual folklore reinforce these demanding ideals, which cannot always be met and hence give rise to anxiety, guilt, and feelings of inadequacy. Premature ejaculation is a common problem, especially for young males. Sometimes this is not the consequence of any psychological problem but the natural result of excessive tension in a male who has been sexually deprived. In such cases, more frequent coitus solves the problem. Premature ejaculation is difficult to define. The best definition is that offered by the American sexologists, William Howell Masters and Virginia Eshelman Johnson, who say that a male suffers from premature ejaculation if he cannot delay ejaculation long enough to induce orgasm in a sexually normal female at least half the time. This generally means that vaginal penetration with some movement (although not continuous) must be maintained for more than one minute. The average American male ejaculates in two or three minutes after vaginal penetration, a coital duration sufficient to cause orgasm in most females the majority of the time. Various methods of preventing premature ejaculation have been tried. One is for the male to excite the female more during the foreplay so that she reaches orgasm more rapidly after penetration, but this technique often excites the male as well and defeats its purpose. Another common method is for the male to think of nonsexual matters, which may prove effective but reduces his pleasure. The most effective therapy is that advocated by Masters and Johnson in which the female brings the male nearly to orgasm and then prevents the male's orgasm by briefly compressing the penis between her fingers just below the head of the penis. The couple come to realize that premature ejaculation can thus be easily prevented, their anxiety disappears, and ultimately they can achieve normal coitus without resorting to this squeeze technique. Erectile impotence is almost always of psychological origin in males under 40; in older males physical causes are more often involved. Fear of being impotent frequently causes impotence, and, in many cases, the afflicted male is simply caught up in a self-perpetuating problem that can be solved only by achieving a successful act of coitus. In other cases, the impotence may be the result of disinterest in the sexual partner, fatigue, distraction because of nonsexual worries, intoxication, or other causes—such occasional impotency is common and requires no therapy. Some males, however, are chronically impotent and require psychotherapy or behaviour therapy. Such impotency is thought to be the result of deep-seated causal factors such as unconscious feelings of hostility, fear, inadequacy, or guilt. Primary impotence, the inability to ever have achieved erection sufficient for coitus, is more difficult to treat than the far more common secondary impotence, which is impotence in a male who was formerly potent. Ejaculatory impotence, the inability to ejaculate in coitus, is quite rare and is almost always of psychogenic origin. It seems associated with ideas of contamination or with memories of traumatic experiences. Occasional ejaculatory inability may be expected in older men or in any male who has exceeded his sexual capacity. vaginismus is a powerful spasm of the pelvic musculature constricting the vagina so that penetration is painful or impossible. It seems wholly due to antisexual conditioning or psychological trauma and serves as an unconscious defense against coitus. It is treated by psychotherapy and by gradually dilating the vagina with increasingly large cylinders. dyspareunia, painful coitus, is generally physical rather than psychological. It is mentioned here only because some inexperienced females fear they cannot accommodate a penis without being painfully stretched. This is a needless fear since the vagina is not only highly elastic but enlarges with sexual arousal, so that even a small female can, if aroused, easily receive an exceptionally large penis. Disparity in sexual desire constitutes the most common sexual problem. It is to some extent inescapable, since differences in the strength of the sexual impulse and the ability to respond are based on neurophysiological differences. Much disparity, however, is the result of inhibition or of one person having been subjected to more sexual stimuli during the day than the other. The partner who has been seeing sexually attractive persons periodically during the day and who may have had an opportunity to relax on the way back from the office or store is naturally more interested in coitus than the partner who has not been exposed to sexual stimuli. Another cause of disparity is a difference in viewpoint. Perhaps one person anticipates coitus as a palliative to compensate for the trials and tribulations of life, whereas another may be interested in sex only if the preceding hours have been reasonably problem-free and happy. Even in cases of neurophysiological differences in sex drive, the less-motivated partner can be trained to a higher level of interest, since most humans operate well below their sexual capacities. Psychological fatigue, a growing disinterest in sexual behaviour with a particular partner, sometimes constitutes a problem. Humans are subject to monotony, and coitus may become routine or even a chore. Lessening frequencies of marital coitus are more often the result of this than of age. The solution lies in varying the time, the setting, and in breaking away from habitual techniques and positions. Preferences for or antipathies toward particular positions, techniques, or times frequently cause trouble. One partner may desire mouth-genital contact or anal stimulation that the other partner finds disagreeable or perverse. Some wish to have coitus in the light, others insist upon darkness; some prefer morning, others evening. The possibilities for disagreement are legion. Even if disagreements stemming from needless inhibition are overcome, there still remain disparities in preference, and these should be met by the philosophy that, by giving pleasure to another, one obtains pleasure. Needless to say, no partner should insist upon that which is abhorrent to the other after the latter has made honest attempts to cooperate. Lack of female orgasm, anorgasmy, is a very frequent problem. One should differentiate between females who become sexually aroused but do not reach orgasm and those who do not become aroused. Only the latter merit the label frigid (frigidity). It is common for females not to achieve orgasm during the first weeks or months of coital activity. It is almost as though many females must learn how to have orgasm, for after having had one they respond with increasing frequency. In some cases, the female initially has no idea how to copulate effectively and simply lies passive, expecting the male to bring her to orgasm. Other females resist orgasm because the feeling of being swept away and losing control is frightening. In most cases, however, anorgasmy is simply the result of years of inhibition—having been trained since childhood to avoid yielding to the sexual impulse, it is difficult to metamorphose into a responsive and orgasmic being. In the final analysis, anorgasmy is psychological in origin; few, if any, females lack the neurophysiology necessary for orgasm, and anthropology shows that in sexually permissive societies virtually all females have little difficulty in attaining orgasm in coitus. Anorgasmy is treated by removing inhibitions (inhibition), by teaching coital techniques, and by inducing orgasm through noncoital methods. The effective therapist should also impress upon the female that not reaching orgasm is no sign of failure or inadequacy on her part or her partner's and that sexual activity is very pleasurable to both, even if orgasm does not ensue. Indeed, some females derive great pleasure and satisfaction without orgasm, a fact that should be made known to anxious male partners. Too great a concern over orgasm defeats itself. As Kinsey once pointed out, thinking is the enemy of sexual pleasure, and a female can scarcely have orgasm if she is worrying about whether she will attain it or not and if she senses that her partner is mentally turning the pages of a marriage manual. Lastly, sexual problems are often perpetuated by the inability of the partners to communicate freely their feelings to one another. There is a curious and unfortunate reticence about informing one's partner as to what does or does not contribute to one's pleasure. The partner must function on a trial-and-error basis, ever on the alert for signs indicating the efficacy of his or her efforts. This muteness is even more pronounced when it comes to an individual making suggestions to the partner. Many persons feel that a suggestion or request would be interpreted by the partner that he or she had been inept or at least remiss. As with any other problems, sexual problems can be overcome or ameliorated only if the individuals concerned communicate effectively. Social and cultural aspects The effects of societal value systems on human sexuality are, as has already been mentioned, profound. The American anthropologist George P. Murdock (Murdock, George P.) summarized the situation, saying: All societies have faced the problem of reconciling the need of controlling sex with that of giving it adequate expression, and all have solved it by some combination of cultural taboos, permissions, and injunctions. Prohibitory regulations curb the socially more disruptive forms of sexual competition. Permissive regulations allow at least the minimum impulse gratification required for individual well-being. Very commonly, moreover, sex behavior is specifically enjoined by obligatory regulations where it appears directly to subserve the interests of society. The historical heritage is, of course, the foundation upon which the current situation rests. Western civilizations are basically Greco-Roman in social organization, philosophy, and law, with a powerful admixture of Judaism and Christianity. This historical mixture contained incompatible elements: individual freedom was cherished, yet there was a great emphasis on law and proper procedure; the pantheism of the Greeks and Romans clashed with Judeo-Christian monotheism; and the sexual permissiveness of Hellenistic times was answered by the antisexuality of early Christianity. In terms of sex, the most important factor was Christianity. While other vital aspects of human life, such as government, property rights, kinship, and economics, were influenced to varying degrees, sexuality was singled out as falling almost entirely within the domain of religion. This development arose from an ascetic concept shared by a number of religions, the concept of the good spiritual world as opposed to the carnal materialistic world, the struggle (dualism) between the spirit and the flesh. Since sex epitomizes the flesh, it was obviously the enemy of the spirit. Beginning in the 2nd century, Western Christianity was heavily influenced by this dichotomous philosophy of the Gnostics; sex in any form outside of marriage was an unmitigated evil and, within marriage, an unfortunate necessity for purposes of procreation rather than pleasure. The powerful antisexuality of the early Christians (note that neither God nor Christ has a wife and that marriage does not exist in heaven) was in part due to their apocalyptic vision of life: they anticipated that the end of the world and the Last Judgment would soon be upon them. There was no time for a gradual weaning away from the flesh; an immediate and drastic approach was necessary. Indeed, such excessive antisexuality developed that the church itself was finally moved to curb some of its more extreme forms. As it became evident that human existence was going to continue for some unforeseeable length of time and as occasional intelligent theologians made themselves felt, antisexuality was ameliorated to some extent but still remained a foundation stone of Christianity for centuries. This attitude was particularly unfortunate for women, to whom most of the sexual guilt was assigned. Women, like the original temptress Eve, continued to attract men to commit sin. They were spiritually weak creatures prone to yield to carnal impulses. This is, of course, a classic example of projecting one's own guilty desires upon someone else. Ultimately, legal control over sexual behaviour passed from the church to the state, but in most instances the latter simply perpetuated the attitudes of the former. Priests and clergymen frequently continued to exert powerful extralegal control: denunciations from the pulpit can be as effective as statute law in some cases. Although religion has weakened as a social control mechanism, even today liberalization of sex laws and relaxation of censorship have often been successfully opposed by religious leaders. On the whole, however, Christianity has become progressively more permissive, and sexuality has come to be viewed not as sin but as a God-given capacity to be used constructively. Apart from religion, the state sometimes imposes restrictions for purely secular reasons. The more totalitarian (totalitarianism) a government, the more likely it is to restrict or direct sexual behaviour. In some instances, this comes about simply as the consequence of a powerful individual (or individuals) being in a position to impose ideas upon the public. In other instances, one cannot escape the impression that sex, being a highly personal and individualistic matter, is recognized as antithetical to the whole idea of strict governmental control and supervision of the individual. This may help explain the rigid censorship exerted by most totalitarian regimes over sexual expression. It is as though such a government, being obsessed with power, cannot tolerate the power the sexual impulse exerts on the population. Social control of sexual behaviour Societies differ remarkably in what they consider socially desirable and undesirable in terms of sexual behaviour and consequently differ in what they attempt to prevent or promote. There appear, however, to be four basic sexual controls in the majority of human societies. First, to control endless competition, some form of marriage is necessary. This not only removes both partners from the competitive arena of courtship and assures each of a sexual partner, but it allows them to devote more time and energy to other necessary and useful tasks of life. Despite the beliefs of earlier writers, marriage (monogamy) is not necessary for the care of the young; this can be accomplished in other ways. Second, control of forced sexual relationships is necessary to prevent anger, feuding, and other disruptive retribution. Third, all societies exert control over whom one is eligible to marry or have as a sexual partner. endogamy, holding the choice within one's group, increases group solidarity but tends to isolate the group and limit its political strength. exogamy, forcing the individual to marry outside the group, dilutes group loyalty but increases group size and power through new external liaisons. Some combination of endogamy and exogamy is found in most societies. All have incest prohibitions. These are not based on genetic knowledge. Indeed, many incest taboos involve persons not genetically related (father–stepdaughter, for example). The prime reason for incest prohibition seems to be the necessity for preventing society from becoming snarled in its own web: every person has a complex set of duties, rights, obligations, and statuses with regard to other people, and these would become intolerably complicated or even contradictory if incest were freely permitted. Fourth, there is control through the establishment of some safety-valve system: the formulation of exceptions to the prevailing sexual restrictions. There is the recognition that humans cannot perpetually conform to the social code and that well-defined exceptions must be made. There are three sorts of exceptions to sexual restrictions: (1) Divorce: while all societies encourage marriage, all realize that it is in the interest of society and the individual to terminate marriage under certain conditions. (2) Exceptions based on kinship: many societies permit or encourage sexual activity with certain kin, even after marriage. Most often these kin are a brother's wife or a wife's sister. In addition, sexual “joking relationships” are often expected between brothers-in-law, sisters-in-law, and cousins. While coitus is not involved, there is much explicit sexual banter, teasing, and humorous insult. (3) Exceptions based on special occasions, ranging from sexual activity as a part of religious rites (ritual) to purely secular ceremonies and celebrations wherein the customary sexual restrictions are temporarily lifted. Turning to particular forms of sexual behaviour, one learns from anthropology and history that extreme diversity in social attitude is common. Most societies (primitive culture) are unconcerned over self-masturbation since it does not entail procreation or the establishment of social bonds, but a few regard it with disapprobation. Sexual dreams cause concern only if they are thought to be the result of the nocturnal visitation of some spirit. Such dreams were once attributed to spirits or demons known as incubi (incubus) and succubi (succubus), who sought out sleeping humans for sexual intercourse. Petting among most preliterate societies is done only as a prelude to coitus—as foreplay—rather than as an end in itself. In some parts of sub-Saharan Africa, however, petting is used as a premarital substitute for coitus in order to preserve virginity and avoid pregnancy. There is great variation in petting and foreplay techniques. Kissing is by no means universal, as some groups view the mouth as a biting and chewing orifice ill-suited for expressing affection. While some societies emphasize the erotic role of the female breast, others—such as the Chinese (China)—pay little attention to it. Still others regard oral stimulation of the breast unseemly, being too akin to infantile suckling. Although manual stimulation of the genitalia is nearly universal, a few peoples abstain because of revulsion toward genital secretions. Not much information exists on mouth–genital contact, and one can say only that it is common among some peoples and rare among others. A considerable number of societies manifest scratching and biting in conjunction with sexual (sadism) activity, and most of this is done by the female. Sadomasochism (masochism) in any other form, however, is conspicuous by its absence in preliterate societies. An enumeration of the societies that permit or forbid premarital coitus is complicated not only by the double standard but also by the fact that such prohibition or permission is often qualified. As a rough estimate, however, 40 to 50 percent of preliterate or ancient societies allowed premarital coitus under certain conditions to both males and females. If one were to count as permissive those groups that theoretically disapprove but actually condone such coitus, the percentage would rise to perhaps 70. In marital coitus, when sexual access is not only permitted but encouraged, one would expect considerable uniformity in frequency of coitus. This expectation is not fulfilled: social conditioning profoundly affects even marital coitus. On one Irish island reported upon by a researcher, for example, marital coitus is best measured in terms of per year, and among the Cayapas (Chachi) of Ecuador, a frequency of twice a week is something to boast of. The coital frequencies of other groups, on the other hand, are nearer to human potential. In one Polynesian group, the usual frequency of marital coitus among individuals in their late 20s was 10 to 12 per week, and in their late 40s the frequency had fallen to three to four. The African Bala, according to one researcher, had coitus on the average of once or twice per day from young adulthood into the sixth decade of life. Marital coitus is not unrestricted. Coitus during menstruation or after a certain stage of pregnancy is generally taboo. After childbirth a lengthy period of time must often elapse before coitus can resume, and some peoples abstain for magical reasons before or during warfare, hunting expeditions, and certain other important events or ceremonies. In modern Western society one finds menstrual, pregnancy, and postpartum taboos (taboo) perpetuated under an aesthetic or medical guise, and coaches still attempt to force celibacy upon athletes prior to competition. Extramarital coitus (adultery) provides a striking example of the double standard: it is expected, or tolerated, in males and generally prohibited for females. Very few societies allow wives sexual freedom. Extramarital coitus with the husband's consent, however, is another matter. Somewhere between two-fifths and three-fifths of preliterate societies permit wife lending or allow the wife to have coitus with certain relatives (generally brothers-in-law) or permit her freedom on special ceremonial occasions. The main concern of preliterate societies is not one of morality, but of more practical considerations: does the act weaken kinship ties and loyalty? Will it damage the husband's social prestige? Will it cause pregnancy and complicate inheritance or cause the wife to neglect her duties and obligations? Most foreign of all to Western thinking is that of those peoples whose marriage ceremony involves the bride having coitus with someone other than the groom, yet it is to be recalled that this practice existed to a limited extent in medieval Europe as jus primae noctis (seigneur, droit du), the right of the lord to the bride of one of his subjects. Sexual deviations and sex offenses are, of course, social definitions rather than natural phenomena. What is normative behaviour in one society may be a deviation or crime in another. One can go through the literature and discover that virtually any sexual act, even child–adult relations or necrophilia, has somewhere at some time been acceptable behaviour. Homosexuality is permitted in perhaps two-thirds of human societies. In some groups it is normative behaviour, whereas in others it is not only absent but beyond imagination. Generally, it is not an activity involving most of the population but exists as an alternative way of life for certain individuals. These special individuals are sometimes transvestites (transvestism)—that is, they dress and behave like the opposite sex. Sometimes they are regarded as curiosities or ridiculed, but more often they are accorded respect and magical powers are attributed to them. It is noteworthy, however, that aside from these transvestites, exclusive homosexuality is quite rare in preliterate societies. In conclusion, the cardinal lesson of anthropology is that no type of sexual behaviour or attitude has a universal, inherent social or psychological value for good or evil—the whole meaning and value of any expression of sexuality is determined by the social (social class) context within which it occurs. Class distinctions Differences in sexual behaviour between classes within technologically developed societies are very marked. Civilizations are made up of class hierarchies, and the different subgroups normally develop their own value systems. Most of the knowledge of the sexual behaviour and attitudes of ancient cultures is that of the upper or ruling class; the behaviour and feelings of the slaves and peasants were seldom recorded. There is the impression—probably a correct one—that throughout history the lower socio-economic class was the most permissive. Sex has always been one of the few pleasures of the poor and oppressed. On the other hand, one must not overlook the fact that a fanatical Puritanism can also flourish at the bottom of the social scale, and, hence, one can never assume that low status and sexual permissiveness are inevitably linked. The Kinsey (Kinsey, Alfred Charles) studies showed considerable social class differences in sexuality in the United States, chiefly in that the lower class was more tolerant of nonmarital coitus. More recent studies indicate that these class differences have rapidly broken down. Increased literacy and the influence of mass media have made the population more homogeneous in sexual attitudes. One can find, moreover, reversals of the previous pattern: a lower class person on the way up the social ladder may be quite conservative in his sexual views, feeling that this facilitates upward mobility, whereas the person secure in his or her high social status often feels that he or she can afford to flout convention. Actually, the most sexually liberal are those at the very bottom, who have nothing to lose, and those at the very top, who are beyond social retribution. The great middle class remains the bastion of traditionalism, and it is here that the double standard of morality is most prominent. The intellectualized liberalism of the upper level seeps down only slowly, and the pragmatic egalitarianism of the lower level does not penetrate far upward. Economic influences Systems of production and distribution have had a growing influence on sexual behaviour since the Industrial Revolution. The old family pattern was inexorably disrupted by the rise of the industrial state. Children were no longer kept at home to share in the work and be economic assets but left for school or for nonfamily employment, and the degree of parental control diminished. The “working wife” employed outside the home, once found only among the impoverished, has gradually become the typical wife. With her enhanced economic power and her greater association with people outside the home, she became less a chattel. As the population left the family farm and tight-knit small communities for anonymous big-city existence, not only parental but societal controls over behaviour were weakened. Society became increasingly nomadic with improved transportation and job opportunities. Cultural and ethnic subgroups that formerly would have had little contact were thrown together in the same schools, factories, offices, and neighbourhoods. All of this vast uprooting and rearranging naturally altered sexual attitudes and behaviour. The individual no longer had the option of choosing to conform or depart from a rather clear-cut sexual moral code but instead was faced with a multiplicity of choices of varying degrees of social acceptability. The major sexual change—one still in progress—was the emancipation of women, which brought with it an increasing acceptance of premarital sexual activity, the concept of woman as a human being with her own sexual needs and rights, and the possibility of terminating an unhappy marriage without incurring serious social censure. A second major change was the erosion of simplistic value systems: with increased mobility and social mixing, the individual learned that the values and attitudes he or she had unquestioningly accepted were not necessarily shared by neighbours and co-workers. As a result, life became not only more complex but more permissive. This growing tolerance has in recent decades extended, to a limited extent, to homosexuality. There is no evidence that homosexuality or other deviant behaviour has measurably increased as a result of society's urbanization and technological progress, but one gains the impression of an increase simply because these topics, previously unmentionable, are now openly discussed in the mass media. While the old monolithic value systems broke down and individuals were accorded a wider variety of choices in terms of sexual life, there developed a paradoxical trend toward homogeneity as a result of mobility, the mass media, and increasing economic parity. Geographical and social-class differences in sexual attitudes and behaviour have steadily lessened. The plumber's family and the banker's family are now indistinguishable in terms of dress; both have automobiles; their offspring attend the same schools; and they share the same newspapers, magazines, and television programs. One might summarize by saying that society is homogeneous in that everyone now has available a wide diversity of sexual attitudes and activities. Legal regulation Sex laws, the origins of which, as mentioned above, are found within the church, are unique in one important respect. Whereas all other laws are basically concerned with the protection of person or property, the majority of sex laws are concerned solely with maintaining morality. The issue of morality is minimal in other laws: one can legitimately evict an impoverished old couple from their mortgaged home or sentence a hungry man for stealing food. Only in the realm of sex is there a consistent body of law upholding morality. The earliest sex laws of which there is knowledge are from the Near East and date back to the 2nd millennium BC. They are remarkable in three respects: there are great omissions—certain acts are not mentioned whereas others receive detailed attention; some laws seem almost contradictory; and penalties are often extraordinarily severe. One obtains the distinct impression that these laws were case law—that is, laws formulated upon specific cases as they arose rather than being the result of lengthy judicial deliberation done in advance. These laws influenced Judaic and, hence, Christian thinking, and some were immortalized in the Bible, chiefly in Leviticus. As mentioned earlier, when secular law replaced religious law, there was rather little change in content. In Europe the Napoleonic Code represented a break with tradition and introduced some measure of sexual tolerance, but in England and the United States there was no such rift with the past. In the latter country, as each new state joined the union, its sex laws simply duplicated, to a great extent, those of pre-existing states; legislators were disinclined to debate sexual issues or to risk losing votes by discarding or weakening sex laws. Sex laws may be grouped in three categories: (1) Those concerned with protection of person. These are based on the element of consent. These otherwise logical laws become problematic when society deems that minors, mental retardates, and the insane are incapable of giving consent—hence, coitus with them is rape. (2) Those concerned with preventing offense to public sensibilities. Statutes preclude public sexual activity, exhibitionism, and offensive solicitation. (3) Those concerned with maintaining sexual morality. These constitute the majority of sex laws, covering such items as premarital coitus, extramarital coitus, incest, homosexuality, prostitution, peeping, nudity, animal contact, transvestism, censorship, and even specific sexual techniques—chiefly oral or anal. Laws relating to sexual conduct and morality are generally far more extensive in the United States than in western Europe and most other areas of the world. In recent years, in Europe and the United States, a number of highly respected legal, medical, and religious organizations have deliberated on the issue of the legal control of human sexuality. They have been unanimous in the conclusion that, while laws protecting person and public sensibilities should be retained, the purely moral laws should be dropped. What consenting adults do in private, it is argued, should not be subject to legal control. In the final analysis, sexuality, like any other vital aspect of human life, must be dealt with on an individual or societal level with a combination of rationality, sensitivity, and tolerance if society is to avoid personal and social problems arising from ignorance and misconception. Paul Henry Gebhard Ed. Sexually (sexually transmitted disease) transmitted diseases Infections transmitted primarily by sexual contact are referred to as sexually transmitted diseases (STDs). Caused by a variety of microbial agents that thrive in warm, moist environments such as the mucous membranes of the vagina, urethra, anus, and mouth, STDs are diagnosed most frequently in individuals who engage in sexual activity with many partners. In the past, a disease transmitted sexually was more commonly called a venereal disease, or VD, and was applied to only a few infections such as gonorrhea and syphilis. Actually more than 20 STDs have been identified, and infections caused by Chlamydia trachomatis, herpes simplex virus, and human papillomavirus, although underreported, are believed to be more prevalent than gonorrhea in the United States. Although the incidence of some STDs has reached epidemic proportions, it was not until the advent of the acquired immunodeficiency syndrome (AIDS) that the need to restrain the transmission of these diseases gained serious attention. AIDS is a deadly disease for which there is no known cure. This fact has made prevention of the spread of HIV (see below) infection a top priority of the health-care community, with education concerning safer sexual practices at the fore. The “safe sex” strategy, which includes encouraging the use of condoms or the practice of abstinence, has been introduced to prevent the spread not only of AIDS but of all STDs. Stemming the transmission of disease rather than relying on treatment, which in the case of AIDS does not even exist, is the basic tenet of the safe-sex doctrine. Preventing the transmission of STDs is also important because many of these diseases do not produce initial symptoms of any significance. Thus, they often go untreated, increasing their spread and the incidence of serious complications; untreated chlamydial infections in women are the primary preventable cause of female sterility. Common sexually transmitted organisms Bacteria, parasites, and viruses are the most common microbial agents involved in the sexual transmission of disease. Bacterial agents include Neisseria gonorrhoeae, which causes gonorrhea and predominantly involves the ureter in men and the cervix in women, and Treponema pallidum, which is responsible for syphilis. The parasite Chlamydia trachomatis causes a variety of disorders—in women, urethritis, cervicitis, and salpingitis (inflammation of the ureter, cervix, and fallopian tubes, respectively) and, in men, nongonococcal urethritis. Sexually transmitted viral agents include the human papillomavirus (human papillomavirus), which causes genital warts. Infection by this virus, of which there are more than 20 types, has been linked to cervical carcinoma. herpes simplex virus II is the causative agent of genital herpes, a condition in which ulcerative blisters form on the mucous membranes of the genitalia. Acquired immunodeficiency syndrome (AIDS) AIDS is caused by the human immunodeficiency virus (HIV), a pernicious infectious agent that attacks the immune system, leading to its progressive destruction. The virus is found in highest concentrations in the blood, semen, and vaginal and cervical fluids of the human body and can be harboured asymptomatically for 10 years or more. Although the primary route of transmission is sexual, HIV also is spread by the use of infected needles among intravenous drug users, by the exchange of infected blood products, and from an infected mother to her fetus during pregnancy. The progression of the syndrome does not follow a defined path; instead nonspecific symptoms reflect the myriad effects of a failing immune system. These symptoms are referred to as AIDS-related complex (ARC) and include fever, rashes, weight loss, and wasting. Opportunistic infections such as Pneumocystis carinii pneumonia, neoplasms such as Kaposi's sarcoma, and central nervous system dysfunction are also common complications. The patient eventually dies, unable to mount an immunologic defense against the constant onslaught of infections. A blood test can be used to detect HIV infection before the symptoms begin to manifest themselves, and all individuals who may be at even the slightest risk of infection are encouraged to be tested in order to prevent the unknowing spread of HIV to others. Identification of infection before the onset of the disease, however, does not promise a better prognosis; the vast majority of those infected with HIV will ultimately succumb to AIDS. Although development of a vaccine is being pursued, it is not yet available and education remains the best way to prevent transmission of this lethal disease. Ed. Additional Reading General information may be found in Benjamin B. Wolman and John Money (eds.), Handbook of Human Sexuality (1980, reissued 1993); James Leslie McCary and Stephen P. McCary, McCary's Human Sexuality, 4th ed. (1982); Zira DeFries, Richard C. Friedman, and Ruth Corn (eds.), Sexuality: New Perspectives (1985), a compilation of recent interdisciplinary research; Herant A. Katchadourian, Fundamentals of Human Sexuality, 5th ed. (1989); June M. Reinisch and Ruth Beasley, The Kinsey Institute New Report on Sex: What You Must Know to Be Sexually Literate (1990), a summary of current thinking in sex research; William H. Masters, Virginia E. Johnson, and Robert C. Kolodny, Human Sexuality, 4th ed. (1992); and Janet Shibley Hyde, Understanding Human Sexuality, 5th ed. (1994). A popular treatment of various aspects of sex is found in Stefan Bechtel et al., The Practical Encyclopedia of Sex and Health (also published as The Sex Encyclopedia, 1993). Reference works on human sexuality include Robert T. Francoeur, Timothy Perper, and Norman A. Scherzer (eds.), A Descriptive Dictionary and Atlas of Sexology (1991); Michael A. Carrera, The Language of Sex: An A to Z Guide (1992); and two annotated bibliographies, Mervyn L. Mason, Human Sexuality: A Bibliography and Critical Evaluation of Recent Texts (1983); and Suzanne G. Frayser and Thomas J. Whitby, Studies in Human Sexuality: A Selected Guide (1987).The history of the study of human sexuality is chronicled in Paul Robinson, The Modernization of Sex: Havelock Ellis, Alfred Kinsey, William Masters, and Virginia Johnson (1976); Vern L. Bullough, Sexual Variance in Society and History (1976); Jeffrey Weeks, Sexuality and Its Discontents: Meanings, Myths & Modern Sexualities (1985), and Sex, Politics, and Society: The Regulation of Sexuality Since 1800, 2nd ed. (1989), the latter focusing on Great Britain; Pat Caplan (ed.), The Cultural Construction of Sexuality (1987); John D'Emilio and Estelle B. Freedman, Intimate Matters: A History of Sexuality in America (1988); Sander L. Gilman, Sexuality: An Illustrated History: Representing the Sexual in Medicine and Culture from the Middle Ages to the Age of AIDS (1989); and Janice M. Irvine, Disorders of Desire: Sex and Gender in Modern American Sexology (1990).Significant studies of specifically female or male sexuality in the United States are Alfred C. Kinsey, Wardell B. Pomeroy, and Clyde E. Martin, Sexual Behavior in the Human Male (1948); Alfred C. Kinsey et al., Sexual Behavior in the Human Female (1953, reissued 1973); and Shere Hite, The Hite Report: A Nationwide Study on Female Sexuality, new rev. ed. (1981), and The Hite Report on Male Sexuality (1981), although criticism has been leveled at the studies' methodology.Anthropological overviews of sex are given in Donald S. Marshall and Robert C. Suggs (eds.), Human Sexual Behavior: Variations in the Ethnographic Spectrum (1971); George P. Murdock, Social Structure (1949, reissued 1965); and Clellan S. Ford and Frank A. Beach, Patterns of Sexual Behavior (1951, reprinted 1980), which compares sexual behaviour patterns of nearly 200 human cultural groups worldwide and of a large number of related mammals.Sexual physiology is comprehensively treated in William H. Masters and Virginia E. Johnson, Human Sexual Response (1966, reissued 1986); Loretta P. Higgins and Joellen W. Hawkins, Human Sexuality Across the Life Span (1984), a text for nursing practice; and Simon LeVay, The Sexual Brain (1993), which includes a discussion of the author's report of the size variation of a part of the hypothalamus with respect to sexual orientation among men. William H. Masters and Virginia E. Johnson, Human Sexual Inadequacy (1970, reissued 1980), reports behaviour therapy treatments of sexual dysfunction. Richard Green and John Money (eds.), Transsexualism and Sex Reassignment (1969), discusses sex change. John Money, Gay, Straight, and In-Between: The Sexology of Erotic Orientation (1988), analyzes determining physiological, cultural, and personal history factors.The psychological differences between the sexes and the relationship of gender are analyzed by Robert J. Stoller, Sex and Gender, 2 vol. (1968–75); Eleanor Emmons Maccoby and Carol Nagy Jacklin, The Psychology of Sex Differences (1974); G. Mitchell, Human Sex Differences (1981), a primatologist's investigation; John Archer and Barbara Lloyd, Sex and Gender (1982), also published in an enlarged, revised North American edition with the same title (1985); and June M. Reinisch, Leonard A. Rosenblum, and Stephanie A. Sanders (eds.), Masculinity/Femininity: Basic Perspectives (1987). Biological data is examined by Anne Fausto-Sterling, Myths of Gender: Biological Theories About Women and Men, 2nd ed. (1992).Social and cultural aspects of human sexuality are investigated by Louis M. Epstein, Sex Laws and Customs in Judaism (1948, reissued 1968), a detailed history of Judeo-Christian attitudes toward sex; Derrick S. Bailey, Sexual Relation in Christian Thought (also published as The Man-Woman Relationship in Christian Thought, 1959); Ira L. Reiss, The Social Context of Premarital Sexual Permissiveness (1967), and Journey into Sexuality (1986), a study of the relationship between cross-cultural differences in nonsexual and sexual patterns; Robert Coles and Geoffrey Stokes, Sex and the American Teenager (1985); and Arthur S. Leonard, Sexuality and the Law: An Encyclopedia of Major Legal Cases (1993), restricted, however, to United States law.Diseases transmitted through sexual contact are described in Allan M. Brandt, No Magic Bullet: A Social History of Venereal Disease in the United States Since 1880 (1985); Charles E. Rinear, The Sexually Transmitted Diseases (1986); and L.C. Parish and Friedrich Gschnait (eds.), Sexually Transmitted Diseases: A Guide for Clinicians (1989).
随便看	Spratling, William Spratly Islands Sprat, Thomas spraying and dusting spreadsheet Sprechstimme Spree River Sprengel, Christian Konrad Sprengtporten, G.M. Sprengtporten, J.M., Friherre (baron) spring Spring and Autumn Period spring balance spring beauty springbok Springbok Flats Springer, Axel springer spaniel Springfield Springfield, Dusty Springfield Race Riot Springfield rifle Spring Green spring hare Springhill