It turns out finger size can predict penis size. But it’s probably not quite what you think.

South Korean researchers at Gachon University’s Gil Hospital have found that men whose second and fourth fingers are about the same size have longer penises than their counterparts with more mismatched index and ring fingers.
The scientists made this discovery by measuring the fingers and stretched out penises of 144 volunteers who had been put under because they were also undergoing urological surgery. (The size of a stretched out penis correlates with that of an erect one.)

So the next time you see a woman checking out your fingers, she might not just be looking for a wedding ring.