Born in Woodbine, New Jersey, and educated at Cornell and Harvard, Pincus was research director at the Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts. His most significant work was in reproductive physiology, notably his investigations of human birth control, which led to his developing, with Min Chueh Chang and John Rock, the now famous ‘pill’. This form of oral contraception is based upon the use of synthetic hormones that have an inhibitory effect on the female reproductive system, preventing fertilization but still allowing sexual freedom. Pincus discovered that the steroid hormone progesterone, which is found in greater concentrations during pregnancy, is responsible for the prevention of ovulation in pregnancy. With the development, in the fifties, of synthetic hormones, similar in action to progesterone, Pincus saw the possibility of using such synthetics as oral contraceptives. The first clinical trials were conducted in 1954 and proved extremely successful.

In 1963, Pincus became the first chairman of the Oral Advisory Group of the International Planned Parenthood Federation.