Women have butts and so do men. Full-frontal shots of pubic areas carry the same "wow" factor regardless of sex. But what packs the same punch as a full frontal boob-shot when men are involved? Yes, I know that men have nipples and chests, but those are hardly as sexualized as the female breasts.
Although this area could be found on the female form as well, my vote is for the pelvic indentations found on the male lower abdomen, usually accompanied by some sort of "treasure trail," as illustrated within the yellow box below. I anxiously await your thoughts on this important issue!
