Though I've known a few men who described themselves as heterosexuals, I think they've all turned out on closer examination to admire women more than men, but not to the point of not admiring men at all. "Heterosexual" seems to be more of a society-wide assumption (either "I'm just a regular guy", or "I get less hassle from the straight community if I don't call myself bi") than an accurate description of reality. Of course, I'm extrapolating from a small and biased sample, so firm conclusions should not be drawn.