why do men have nipples?

I agree with ShepardSpy in that we (as men) have nipples because during embryonic development all humans start of as females. Also, despite how useless the male nipple may seem, the male nipple (for some men) is sensitive in that if stimulated that stimulation of the nipple is sexually arousing to some men. For other men the nipples are about as useful as a third arm with no nerve endings.

Something to do with human embryos starting off as female in design,then developing masculine characteristics during the developmental stages in the womb under the influence of hormones.. OR-they're a backup set in case you decide to go for a Gender reassignment at some stage later in life!

Its just a vestigial structure as others have mentioned. It was just easier for evolution to leave them there then to design another way to do it.

My husband and I just talked about that a few days ago...I think it's coz it does help entice men. Though other than that, I really don't know or can think of any reason why it's there.

i don't know both of them...can you pls tell me why women have nipples?

As a couple of people have correctly said, the default setting, if you like, is female - so we all start female, and the nipples are formed then. The deciding factors for the gender you turn out to be all happen after that, but at first you start out female. :)

I have often wondered the same thing myself. It is kind-of pointless. Oh well...I am not going to lose any sleep over it LOL

I'm no doctor but I think that male and female are genetically identical except for the reproductive gene sequences. They would have to be to be compatible with each other when creating new life. Hormones alone determine the size and shape of body parts like the mammary glands (and their nipple exit holes), muscle size, and body hair. Correct me if I'm wrong anybody ; )