>>13802108It does though. Sure making nipples on a man does nothing and carries some small cost in development, but imagine the cost of evolving away from male nipples. Reaching a state where men don't develop them carries many failures along the way and NOT having nipples isn't even advantageous. On top of that you could imagine downsides like occasionally females getting the "don't make nipples" genes turned on randomly early in development resulting in a dead end because that individual can't nurse offspring.
There's just no cost to having them, getting to a state without them is costly and the price for making them is negligible.
