In a conversation with Gretchen Rubin, author of The Happiness Project, we exchanged ideas about the senses, particularly about smell. She mentioned a book she was reading called The Scent of Desire by Rachel Herz. A part of it discussed olfaction as a way for human beings to choose mates and how the birth control pill may be a culprit for divorce.
Research suggests that birth control affects women’s taste in men. It’s all in the MHCs, or major histocompatibility complexes, hidden in the scent of men. Studies show that females prefer men whose MHCs differ from their own, perhaps to increase chances of survival—the resulting offspring will then bear more diverse MHC profiles.
But being on the pill creates a preferential shift towards men with similar MHCs. Relationship troubles can then start when the woman gets off the pill; she begins to be attracted to MHC-dissimilar men and is less attracted to the MHC-similar guy she’s with.
In simpler terms, being on the pill can make you attracted to Mr. Wrong, and you realize it when you get off the pill.
(Read more at Psychogical Science.)