Gregory Goodwin Pincus (April 9, 1903 – August 22, 1967) was an American biologist and researcher who co-invented the combined oral contraceptive pill.

[2] His father was Joseph Pincus, a teacher and the editor of a farm journal, and his mother was Elizabeth (née Lipman), whose family had come from the region that is now Latvia.

He wanted to continue his research on the relationship between hormones and conditions such as (but not limited to) cancer, heart disease, and schizophrenia.

[6] In 1951, Margaret Sanger met Pincus at a dinner hosted by Abraham Stone, the director of the Margaret Sanger Research Bureau and medical director and vice president of the Planned Parenthood Federation of America (PPFA), and procured a small grant from the PPFA for Pincus to begin hormonal contraceptive research.

Pincus, along with Min Chueh Chang, confirmed earlier research that progesterone would act as an inhibitor to ovulation.

Puerto Rico was selected as a trial site in 1955, in part because there was an existing network of 67 birth control clinics serving low-income women on the island.

Pincus and Rock disagreed with Rice-Wray based on their experience with patients in Massachusetts and their research found that placebos caused similar side effects.

[7] Pincus' birth control pill changed family life in a significant way, because it allowed women to choose—for the first time—when they would have children and plan accordingly around this decision in a deliberate manner.