look, I asked u a question and answered me with another question! I dunno whats the usage of nipples on boys. I dont know and you dont know too. but at least I know usage of ur nice tools! I asked u if they are useless why u have them?
Well, I know, it's just a part of sex differentiation, bones of luck fall this way and men have nipples to but no need for them. We are just machines executing amino acid programs which were developed by random permutaions and few forms of selection. Nothing there is "by design", so asking "why men have prostate close to their ass" in as stupuid as asking why spiders have eight legs, even though we have only two. Because it works fine.