Although she's also known as a highly controversial figure for her avocation of eugenics, it's safe to say that the birth of the pill started with Margaret Sanger, founder of Planned Parenthood. In 1912, Sanger, a nurse, wrote about the possibility of a "magic pill" that women could take to prevent conception. In her work, she saw many women who died or were injured as a result of self-induced abortions and others who suffered from the health effects of multiple childbirths. Not only would the magic pill improve women's health both physically and mentally, Sanger reasoned, it would also allow them to find more enjoyment in sexual intercourse because they could decide when and if they wanted to become pregnant. In 1914, she began writing a newsletter called "The Woman Rebel" in which she coined the term "birth control."
In the late 1920s, scientists identified both progesterone and estrogen and became aware of their roles in conception and pregnancy. Research into the possibility of a medication to prevent ovulation began in earnest, but it was initially too expensive to order the hormones, then synthesized from animals. In 1941, Dr. Russell Marker discovered a way to synthesize progestin (the synthetic form or progesterone) from wild yams, making research more affordable.