manipulation of the genital organs for pleasure, usually to orgasm. The term masturbation generally connotes self-manipulation, but it can also be used to describe manipulation of or by a sexual partner, exclusive of sexual intercourse. Once the object of extravagant superstitions and severe taboos, masturbation by adults was frowned upon in the majority of premodern societies. Christian moral teaching condemned it as the sin of Onan, who in the Old Testament was censured for spilling his seed; and the Roman Catholic church (Roman Catholicism) still officially condemns masturbation as a mortal sin.

The American researcher Alfred Kinsey (Kinsey, Alfred Charles) and others estimated that at mid-20th century at least 92 percent of all American males and 70–80 percent of all females have indulged in masturbation, and European studies show comparable figures.

The stigma against masturbation is decreasing, and many students of sexual behaviour extoll its virtues as being healthy, pleasurable, sedative, and a release of tension. Masturbation is a widely used element in sex therapy.