A growing body of research on romantic attraction has focused on the importance of altruism: Men who display helping behaviors are generally perceived as more attractive than those who don't.

That said, science does indicate that, generally speaking, straight men tend to find one particular body type the most attractive. And unsurprisingly, it all boils down to survival of the fittest.

An curved arrow pointing right. We already revealed the physical traits that make women attractive to men. Now we have a group of traits that make men attractive to women. Produced by Graham Flanagan.