think about this-
women always say they want a confident guy, yet most women are more self concious about their body than men are...
its best to just not think about it, our logical minds can't comprehend what the emotional minds of women go through, and how they come up with their crazy (to us) decisions
*edit*
i doubt it has to do with performance in bed,
it's not really something you can gauge when you first meet them
who would screw and ugly person out of curiousity as to how good they were in bed?