Why Do Men Have Nipples?

Most of us have a general idea of the theory of evolution and natural selection. All organisms are designed for survival and reproduction. As such, all the physical characteristics of an organism, humans included, are meant to serve a purpose.

But what purpose could male nipples possibly serve? Why do men have nipples in the first place?

The reason actually has very little to do with evolution and everything to do with early human development in the womb.

Early womb development

To arrive at an answer to the male nipple question, we have to start very early in development. Think of an embryo in its early stage, which is considered weeks three through eight of gestation. During this period, all human beings have the same genetic blueprint.

"The XX and XY embryo develop the same until differentiation occurs around nine weeks gestation," said Maureen Whelihan, M.D., the director of Elite GYN Care of the Palm Beaches in Florida.

The eggs produced by the ovaries carry an X chromosome, while sperm could carry either an X or a Y chromosome. Depending on the combination of chromosomes, the baby is either female (XX) or male (XY).

Once the pair of chromosomes is determined, certain hormones are produced.

Testosterone is the hormone in charge of the development of the male genitalia. It is also responsible for the type of bone mass, fat distribution, muscle mass and strength associated with men.

A hormone called estrogen develops the sex organs for females, controls menstruation and affects other physical changes.

Why do men have nipples?

Whelihan said both sexes have nipples and areolae. However, the influences of progesterone and estrogen during puberty lead to the development of female breasts, areolae and nipples. Male nipples do remain a body part, however.

The purpose of nipples in females is to deliver milk to children, Whelihan explained. Certain conditions can make the breasts produce milk in the absence of pregnancy, including pituitary microadenoma.

On the other hand, male nipples are not created for breastfeeding and are considered vestigial structures, like the coccyx or tailbone.

"When men produce too much estrogen—because of obesity or taking supraphysiologic [super-high] doses of testosterone—they can get breast growth called gynecomastia," Whelihan said. "Transgender women can also produce natural breasts when taking feminizing hormones."

Nipples as stimulants

That doesn't mean male nipples have no use, however. Nipples, regardless of a person's sex, are actually erogenous zones that could enhance sexual arousal.

"Nipples have hundreds of nerve endings, making them extremely sensitive as an erogenous zone and sexually stimulating," said Hana Patel, M.B.B.S., a general practitioner and mental health coach in London.

In fact, it's even possible to have orgasms from male nipple play.

"Research and evidence show that nongenital orgasms are possible, and 1 in 10 of us can achieve this," Patel said. "Orgasms are a complex experience and multifaceted, requiring adequate nerve stimulation—there are hundreds in our nipple area—an emotional connection with our partner and the sexual act."

But you shouldn't necessarily incorporate nipple play right away, especially when accompanied by a partner. It's best to talk about things beforehand.

"Lots of men get aroused with nipple stimulation and it should be incorporated into sexual play until you find out differently," Whelihan added. "Some men and women hate their breasts being stimulated. This is important to disclose so that it does not interrupt an intimate encounter."

Nipple play all comes down to getting to know yourself and how you like to be stimulated. But at least you might be able to find a use for those "useless" male nipples.