Why Do Men Have Nipples?

If you want to know why both men and women have nipples, you have to go all the way back to the first few weeks after conception. Nipple development starts about one week before sexual differentiation occurs in embryos. Once the hormone testosterone and the Y chromosome in a male embryo trigger the growth of a penis and testicles, the nipples have already developed, and men are stuck with them for life.

If a male takes enough female hormones, there is a very slim chance that their existing breast tissue could convert to lactating tissue and produce breast milk. However, spontaneous lactation in males who are not taking hormonal supplements should never be taken lightly. It could be a sign of a serious underlying hormonal imbalance or even cancer.

Contrary to popular belief, men’s nips aren’t just there for pec-oration. Both men and women have the same bundle of nerves in their nipples, so they are often just as sensitive as women’s. Nipple stimulation causes the body to release oxytocin, a pleasure hormone, and some say it’s even possible for men to achieve a nipple orgasm.

Gynecomastia is a relatively common condition where a man starts developing excess breast tissue, which results in what looks like small female breasts. His nipples might also become enlarged and tender. Gynecomastia is not the same thing as the chest fat that occurs when a man is very overweight, despite the similar appearance. Gynecomastia usually caused by hormonal imbalances, a tumor in the pituitary gland, or anabolic steroids, and it’s most often seen in older men, newborns, and boys going through puberty.

The procedure is very different than female breast reduction. While both operations are performed by plastic surgeons under local or general anesthesia, depending on the severity of the condition, the goals of the procedures are completely different. Gynecomastia surgery removes excess breast tissue using liposuction and cutting out excess skin in the breasts to flatten the chest. Female breast reduction surgery, on the other hand, opts to remove excess heaviness and volume from the breasts.

Men have breast tissue just like women, although they have far less of it, and for that reason, they can get cancer in their breasts too. Breast cancer is most common in older men, but it can occur at any age, so it’s a good idea for both men and women to keep an eye out for lumps, or changes around the nipples and areola, during skin exams.

Roughly six percent of the population of both men and women has polymastia, which means they have “accessory nipples,” also known as “supernumerary nipples.” There have been cases where people have had as many as eight extra nipples! Fun fact: women’s accessory nipples can become enlarged during lactation and produce milk if they have enough glandular tissue behind them.

On the opposite end of the spectrum, it’s also possible to be born without any nipples at all -- a condition called athelia.

Hairy nips are not just a guy thing -- women sometimes have hair around their areolas too, and although many aren’t a fan of it, it’s perfectly natural. Removing hair from this area requires extra care -- the skin is thin and super sensitive, and chemical hair removal can result in painful burns. That said, if a woman suddenly notices a rapid onset of hair growth around her nipples that was never there before, it could be a sign that her hormones are out of whack and it could be time for a checkup.

No, those little raised bumps that both men and women sometimes have around their nipples are not pimples, so put your zit cream away, and don’t try to “pop” them! They’re areolar glands, or Montgomery glands, a perfectly normal feature of the areola that keeps the area comfortably lubricated. These little bumps can come and go over time, but as long as they don’t keep growing or changing rapidly, they’re probably nothing to worry about.

There are four different nipple shapes: flat, protruding, inverted, and unclassified. It’s also normal to have breasts with nipples that are different sizes or shapes from one another. If you have “innies” instead of “outies,” don’t worry -- inverted nipples are perfectly normal and usually aren’t something to be concerned about.