why do male have nipples. looks like just another useless thing like an appendix?

Answer 1

All mammalian fetuses start out as female. By the time those destined to be male are distinguished, the nipples have already started to form.

Answer 2

The thing is, for most of our evolutionary past, nipples were essential, in that you couldn't just go to the store for milk, and babies can't eat just anything. If a problem were ever to arise on the genetic level (in any parent), such as the deactivation of a gene, that could cause nipples to fail to develop, it could be expressed in children of both sexes. Female children with the trait would be evolutionary dead ends because they would be unable to suckle their young, so the trait would not be passed on. As for males, they might become fathers, or they might be selected against by the females for looking abnormal (or, in the case of more intelligent hominids who may or may not have seen it happen, perhaps for being potential fathers of children that would wither).
In any case, at no point in our history were nipples in males ever detrimental to a male's fitness, so no evolutionary selective force would have pressured us to lose them.

The appendix, though, was at least useful in our past.

Answer 3

Becaue the males and females are the same in utero until the later stages when either female or male genetalia are formed. On a side note... I kinda like the nipples. They give me something to play with.

Answer 4

Well, there are men and women in the world, there are some same things and different things between them, i think nipples are the same things .

Answer 5

man nipples are for homosexuals, gay guys, or same sex oriented men, oh heck what am i supposed to call them this week? you know.

Answer 6

Aestetic purpose,perhaps, Flat would be ugly, don't you think so?

Answer 7

It's really obvious! - it's "just in case....."
you never know, do you....?