I think we all wonder why men have nipples if there is no use for it. Well, there is a reason for it. You see the mammary cells starts to form in the embryo very soon. But its only after some time period that the chromosomes which are responsible for the gender determination determines the gender. That is the chromosomes(Y) determines the embryo is a male only after the mammary cells are formed. Mystery solved!
This is a very interesting fact indeed. I've always wondered what the point is with nipples on men. For us women we feed our young with them. I guess if men were born with out them, in someway they would look incomplete, thanks for such an interesting fact.