Years of disappointment had taught Pincus that it wasn’t always the science that determined an experiment’s success; it was often the forces surrounding the science, including public sentiment. Now that Pincus had settled roughly on the hormone progesterone as the key to his pill, he needed to build the team to do the scientific work, forge alliances with manufacturers, conduct his trials, and, if all went well, spread the news of the coming invention so that it might have a chance at acceptance.

He knew that his progestins (synthetic forms of progesterone) stopped ovulation in rabbits and rats. The next step was to test them on women. And to do that, he would have to add a player to his team—a doctor who could reassure patients they were safe and would convey to the drug companies supplying the drugs that no one would be harmed. There had never been a medicine made for healthy people before—and certainly not one that would be taken every day. The risks were enormous. Pincus settled on a physician named John Rock, a gynecologist respected by his peers and adored by his patients. Rock looked like a family physician from central casting in Hollywood: tall, slender, and silver-haired, with a gentle smile and a calm, deliberate manner. Even his name connoted strength, solidity, and reliability.

Rock had one more thing going for him: He was Catholic.

There is no mention of contraception in the Bible, Old Testament or New, nor did the term enter the vocabulary of Catholic moral theology until the second half of the twentieth century. Before then, the most relevant term used by theologians was onanisma, from the biblical story of Onan (Genesis 38:4–10), which was described as masturbation or sexual intercourse performed without the intention of reproduction. Sex was only for procreation, the Christian church declared, which made onanisma a sin.

The human reproductive system was poorly understood even in the early years of the twentieth century. Many people thought women were merely the vessels, and that the man’s seed sprung on its own into a baby. That’s why spilling seed, or losing semen, whether in sex or masturbation, was labeled a sin.

Still, the Catholic Church had no official position on birth control until 1930, when Pope Pius XI issued a papal encyclical called “Casti Connubii” (Latin for “Of Chaste Wedlock”). The pope acknowledged that birth control was widely used “even amongst the faithful,” although he wasn’t happy about it, and called this trend “a new and utterly perverse morality.” He added that it amounted to a “shameful and intrinsically vicious” attempt to get around the natural “power and purpose” of the conjugal act. The pope did, however, offer the faithful an important loophole: A married couple would not be sinning, he said, if the husband and wife knew that natural reasons prevented them from having children.