Don't pair up with matching genes

New Scientist reports:

They say opposites attract -- and a couple's differences may be key to lasting happiness, according to a new genetic study of people in relationships. The findings were so predictive, that a DNA test could one day reveal how likely a woman is to cheat on her partner, the study suggests. ...

The study revealed that as MHC genetic similarities increased, it was the women who were the most dramatically affected. They were less sexually responsive to their partners, more likely to have affairs, and more attracted to other males, particularly during fertile days of their menstrual cycles, Garver-Apgar says. In relationships where MHC genetic differences were significant, these potentially relationship-splitting behaviours were either absent or greatly reduced. ...

Men were an entirely different matter, the study showed. They did not seem to be affected by genetics at all. As MHC similarities increased, men showed no change in the sexual interest that they had for their partners and seemed no more attracted to women outside of their primary relationship.

Got that men? Find a women with MHC genetic differences, or she will have uncontrollable urges to cheat.