Prior to the second world war, birth control was prohibited in many countries, and in the United States even the discussion of contraceptive methods sometimes led to prosecution under Comstock laws. The history of the development of oral contraceptives is thus closely tied to the birth control movement and the efforts of activists Margaret Sanger, Mary Dennett, and Emma Goldman. Based on fundamental research performed by Gregory Pincus and synthetic methods for progesterone developed by Carl Djerassi at Syntex and by Frank Colton at G.D. Searle & Co., the first oral contraceptive, Enovid, was developed by E.D. Searle and Co. and approved by the FDA in 1960. The original formulation incorporated vastly excessive doses of hormones, and caused severe side effects. Nonetheless, by 1962, 1.2 million American women were on the pill, and by 1965 the number had increased to 6.5 million. The availability of a convenient form of temporary contraceptive led to dramatic changes in social mores including expanding the range of lifestyle options available to women, reducing the reliance of women on men for contraceptive practice, encouraging the delay of marriage, and increasing pre-marital co-habitation.