"What Pike discovered in Japan led him to think about the Pill, because a tablet that suppressed ovulation—and the monthly tides of estrogen and progestin that come with it—obviously had the potential to be a powerful anti-breast-cancer drug. But the breast was a little different from the reproductive organs. Progestin prevented ovarian cancer because it suppressed ovulation. It was good for preventing endometrial cancer because it countered the stimulating effects of estrogen. But in breast cells, Pike believed, progestin wasn’t the solution; it was one of the hormones that caused cell division. This is one explanation for why, after years of studying the Pill, researchers have concluded that it has no effect one way or the other on breast cancer: whatever beneficial effect results from what the Pill does is cancelled out by how it does it. John Rock touted the fact that the Pill used progestin, because progestin was the body’s own contraceptive. But Pike saw nothing “natural” about subjecting the breast to that heavy a dose of progestin. In his view, the amount of progestin and estrogen needed to make an effective contraceptive was much greater than the amount needed to keep the reproductive system healthy—and that excess was unnecessarily raising the risk of breast cancer. A truly natural Pill might be one that found a way to suppress ovulation without using progestin. Throughout the nineteen-eighties, Pike recalls, this was his obsession. “We were all trying to work out how the hell we could fix the Pill. We thought about it day and night.”"