American endocrinologist whose work on the antifertility properties of steroids led to the development of the first effective birth-control pill.

Pincus was educated at Cornell University and Harvard University (M.S., Sc.D., 1927) and also studied in England and Germany. He was a faculty member at Harvard (1931–38), Clark University in Worcester, Mass. (1938–45), Tufts Medical School in Medford, Mass. (1946–50), and Boston University (1950–67).

In 1944 Pincus and Hudson Hoagland founded the Worcester Foundation for Experimental Biology, which became an important centre for the study of steroid hormones and mammalian reproduction. Margaret Sanger encouraged his work, and in 1951 Pincus and his collaborators began to work with synthesized hormones and the prevention of pregnancy. They found that inhibition of ovulation was an effective means of preventing pregnancy in laboratory animals and moved to perfect an oral contraceptive for women.

Pincus' publications include The Eggs of Mammals (1936) and The Control of Fertility (1965). He also edited a number of monographs on aspects of hormones.