"In fact, although the majority of oral contraception brands include inactive pills in their packages, there's no actual medical justification for this—gynecologists have deemed withdrawal bleeding medically unnecessary for years now. For many women on hormonal birth control, this raises a very valid question: Why the hell am I bleeding every three weeks if I don't have to be? The answer, weirdly, lies within the Catholic Church. The church views birth control as a sin, with one important exception: "A married couple would not be sinning… if the husband and wife knew that natural reasons prevented them from having children," according to Jonathan Eig, a journalist who has written an extensive history of the development of the pill. Under prevailing church dogma, the "rhythm method"—in which married couples track their ovulation cycle and engage in non-procreative sex during the "safe periods" where the woman isn't ovulating—is natural in this way. This byzantine and slightly confusing belief matters because one of the scientists who helped develop the birth control pill, John Rock, was a devout Catholic. He was convinced, however naively, that the church would accept the pill as a form of "natural" contraception if it were presented in the right light."