Why do men have nipples?

Answer 1

They're vestigal structures on men, meaning they have no use, but they're there because they don't harm us even though they don't help us. It's an evolution thing. Just like how we have appendixes which are vestigal, but won't disappear even though they're harmful when infected, because they get removed by doctors. I probably confused you.

Answer 2

According to The Straight Dope:

As you may know, every human being gets a unique set of 23 pairs of chromosomes at conception. These fall into two categories. One pair of chromosomes determines sex--the XX combination means you become female, the XY combination means you become male.

The other 22 pairs, the non-sex chromosomes (they're called autosomes), supply what we might call the standard equipment that all humans get. These 22 pairs constitute an all-purpose genetic blueprint that in effect is programmed for either maleness or femaleness by the sex chromosomes. The programming is done by the hormones secreted by the sex glands.

For example, the autosomes give you a voice box, while the sex hormones determine whether it's going to be a deep male voice or a high female voice. Similarly, the autosomes give you nipples, and the sex hormones determine whether said nipples are going to be functioning (in females) or not (in males).

One interesting consequence of the developmental set-up just described is that during the very early stages of fetal life, before the sex hormones have had a chance to do their stuff, all humans are basically bisexual. Among other things, you have two sets of primitive plumbing--one male, one female. Only one set develops into a mature urogenital system, but you retain traces of the other for the rest of your life.

It's tempting, therefore, to say that male nipples are yet another vestige of your carefree bisexual youth. Trouble is, male nipples are hardly vestigial. They're full-sized and fully equipped with blood vessels, nerves, and all the usual appurtenances of functioning organs. Why this should be so nobody knows--in some other mammals, such as rats and mice, male nipple development is completely suppressed by the male sex hormones. (Incidentally, don't start thinking that at one time our human male ancestors must have suckled their young. So far as anybody knows, male lactation has never developed in any mammalian species.)

Human nipples appear in the third or fourth week of development, well before the sex characteristics. (The sex hormones start to assert themselves at seven weeks.) As many as seven pairs of nipples are arranged along either side of a "milk line," a ridge of skin that runs from the upper chest to the navel.

Normally only one pair amounts to anything, but on about one baby in a hundred you can detect some vestige of the other ones, usually on the order of a freckle. There are cases of women who ended up with an extra breast, which made them freak show candidates not so many years ago. Luckily today the women can avail themselves of corrective surgery while the rest of us can watch Jenny Jones.

Anyway, both male and female babies are born with the main milk ducts intact--the gland that produces milk is there in the male, but it remains undeveloped unless stimulated by the female hormone, estrogen. Occasionally, a male baby is born with enough of his mother's estrogen in his body to produce a bizarre phenomenon known as "witches' milk," with the male glands, suitably stimulated, pumping away at the moment of birth.

In the adult male, the dormant glands can still be revived by a sufficient dose of estrogen. Actual lactation is rare--only a couple cases have been recorded. But at least one writer (Daly, 1978) has suggested that the "physiological impediments to the evolution of male lactation do not seem individually surmountable." Meaning we may yet see the dawn of the truly liberated household.

Answer 3

I've also heard that men if sufficiently stimulated can nurse; i.e. they can produce milk for nursing babies. What does stimulated mean? It could mean receiving estrogen (as someones says below), but supposedly the action of a baby sucking and the sufficient desire of the man to nurse may be sufficient! believe it or not.

Answer 4

I have read that when we are in the womb, our bodies begin to develop the same way, including the nipples, before our genitals begin to develop.

Answer 5

Don you think tat without nipple, our body will be super ugly? It will be like a women with breast.

Answer 6

men have nipples cuz they are human beings ,silly

Answer 7

the same reason women have nipples, other than to breast-feed

Answer 8

To make suckers out of women.

Answer 9

because God made men that way

Answer 10

It's so you have something to tweek and pinch