We all know oral contraceptives are useful—for reducing flow and cramps and preventing unplanned pregnancies. The surprise is that the Pill may also lead to unintended romantic quandaries. A U.K. study found that women who were on oral contraceptives when they met their partners were, years later, likelier than non-users to be turned-off, sexually dissatisfied
and eager to fantasize about an affair. But here's the interesting part: They were also generally more satisfied with their partner's (non-sexual) contributions, and therefore less likely to separate. The researchers explain: Under Pill-driven conditions of high-progesterone and low fertility, women go for relationship-worthy qualities such as wealth and intelligence more than high-testosterone traits (biceps and block jaws) that are associated with flings. Oral contraceptives may also lead women to reverse their usual preferences in male body odor. Once a woman goes off the Pill, her other instincts complicate the relationship.