The evolutionary psychologists are at it again. In this mode of thinking, as you should expect, a man is perceived as attractive when in fact he's got good "reproductive potential." So dance like you could impregnate a woman with a healthy baby and she'll think you're a good dancer. The scientists have provided an animation to demonstrate the technique — ironically using a genitalia-free computer figure.
ADDED: An emailer said that reminds him of this — which I think is adorable (but don't say "retarded," because that's wrong... plus: it isn't. It's awesome.)