Birth control pill may alter women's taste in guys

New research suggests that the birth control pill can affect some women's taste in men. The reason is that the pill seems to shift a woman's preference toward men who share a particular group of genes with them. The genes, the major histocompatibility complex (MHC) gene family, are expressed in odor. From Scientific American:

Women who start or stop taking the pill, then, may be in for some relationship problems. A study published last year in Psychological Science found that women paired with MHC-similar men are less sexually satisfied and more likely to cheat on their partners than women paired with MHC-dissimilar men. So a woman on the pill, for example, might be more likely to start dating a MHC-similar man, but he could ultimately leave her less sexually satisfied. Then if she goes off the pill during the relationship, the accompanying hormonal changes will draw her even more strongly toward more MHC-dissimilar men. These immune genes may have a “powerful effect in terms of how well relationships are cemented,” says University of Liverpool psychologist Craig Roberts, co-author of the August paper.

"Birth Control Pills Affect Women's Taste in Men" (Thanks, Marina Gorbis!)