While John Rock was involved in the development of the pill, calling him "the man behind the pill" is a bit disingenuous. Gregory Goodwin Pincus and Min Chueh C

While John Rock was involved in the development of the pill, calling him "the man behind the pill" is a bit disingenuous. Gregory Goodwin Pincus and Min Chueh Chang are the two that probably closer to that description. It should also be noted that John Rock was a vocal proponent of birth control long before the pill. In 1931, he was the only Catholic physician to sign a petition asking Massachusetts to end its ban on birth control (including teaching about it). However, it was in fact Pincus that suggested a 20-day regimen to Rock in their first collaborative study, specifically because withdrawal bleeding would reassure the women that they weren't pregnant. When the pill was new, pregnancy tests weren't easily available at drug stores for cheap. The pill was approved as birth control in 1960 and it wasn't 1977 that at-home pregnancy tests were available in the United States. Having a period was an assurance that the pill was working. Rock did a lot for the pill and was a huge force behind it. He did want the Catholic Church to see it as a variant of the rhythm method. However, the reason behind the withdrawal bleeding is more likely to be about the reassurance that one isn't pregnant. Given the lack of at-home pregnancy tests for the first 17 years of the pill's existence, withdrawal bleeding meant that you weren't pregnant. Event today, many people think skipping periods is weird or unnatural without any religious overtone to it.