This study done by Indiana University's Department of Psychological and Brain Sciences says that guys are clueless when it comes to women's visual cues when trying to determine whether the woman is being friendly, sexual, sad, or rejecting.
Traditionally the argument has been that guys interpret every cue from women as a sexual advance. The researchers say that guys misinterpreted both friendly and sexual cues, so therefore they're just clueless or less able to communicate all around.
I'm still not convinced. I still think there's a biological advantage for men who misinterpret cues as sexual, whether the cues are or not. Maybe these college age kids weren't as sexually aggressive as others. Maybe men are intimidated by women in this new age of political correctness. I also imagine it has to do with the context. If a woman flashes a man a small at the bar versus the library, what is he going to think?
In another study, researchers found that people who are socially awkward make the best long-term mates (score one for the nerds!).