A number of women I've talked to have observed that men prefer their partners to be "less intelligent," stemming from the supposedly natural male need to exercise more control/authority/dominance in a relationship. It doesn't mean that women ought to literally dumb themselves down in order to keep a mate, or withhold making statements that would zap IQ points from the guy, but more like to impress upon the guy that, well... he's the guy.
You could look at it this way. Men = brains = decision making. Women = heart = nurturing and supporting. And, when in a relationship, women aren't supposed to cross into the province that traditionally belongs to men.
What do you think? (Homosexuals can answer as well.)