Although any biological sex has nipples, the functions of nipples can differ. For a person of any sex, nipples can be an erogenous zone. However, the postpartum function of the nipple in people assigned female at birth is to aid in breastfeeding.

In this article, we look at some more interesting facts about nipples.

One of the facts about nipples is babies, like the one pictures, nurse from them to get all of their nutrition.Share on Pinterest
Nipples come in many shapes, colors, and sizes, and they can change shape during pregnancy.

Here are some facts about nipples:

1. The nipples can be an erogenous zone for both sexes.

According to a 2020 article, nipple stimulation plays an important role in the sexual satisfaction of about 80% of females. The authors concluded that using a topical formulation that stimulates the nipples 30 minutes before sexual activity can improve orgasmic satisfaction, strength, and pleasure.

Although male breasts are less well-studied, a 2017 article states that nipples are an erogenous zone for males.

2. Nipples can be hairy.

According to Planned Parenthood, it is normal to have hairs around the nipples.

Hair can be present around the nipples in both males and females.

3. Why do males have nipples?

In mammals, once an embryo has formed, it has the potential to become either male or female.

The nipples form very early in gestation, which is why males also have nipples.

The genes responsible for the development of reproductive organs do not become activated until a later stage.

4. Accessory nipples exist.

Sometimes, a person may have an extra nipple or set of nipples.

According to the Genetic and Rare Diseases Information Center, these are known as supernumerary nipples, and they are a common congenital abnormality. They most frequently occur along the embryonic milk lines, just like in other mammals.

One 2016 article estimates that roughly 1–5% of the population has a supernumerary nipple.

Although most people have just one extra nipple, there have been at least two cases of people with seven nipples.

5. Nipples can occur anywhere on the body.

Although accessory nipples typically occur along the mammary crests, or milk line, they can appear anywhere on the body.

There has been a case of an accessory nipple occurring on the foot, for example.

6. Some people are born without nipples at all.

Known as athelia, this is a rare condition in which a person is born without any nipples.

7. A set of nipples holds a Guinness World Record.

According to the Guinness World Records, in 2013, a person used their nipples to lift 71.87 pounds.

8. There are different types of nipples.

Nipples can be flat, protruding, or inverted.

According to the Center for Young Women’s Health, roughly 10–20% of females have an inverted nipple on at least one breast.

Although this will not affect a person’s health, it is important to keep inverted nipples clean.

9. Breastfeeding is still possible with inverted nipples.

Although inverted nipples can make it more difficult to breastfeed, they do not make it impossible.

According to the World Health Organization (WHO), an inverted nipple can sometimes be nonprotractile, meaning that it does not stretch out when a person pulls it. Instead, the tip goes inward.

In these cases, it is often more difficult for the baby to attach to the nipple. However, protractility often improves during pregnancy and in the first week or so after a baby is born. Otherwise, there are alternative ways to breastfeed successfully with inverted nipples.

10. Breastfeeding females can spontaneously leak milk if they hear babies crying.

This effect is called the let-down reflex.

The let-down reflex occurs when the nerves in a person’s breast send signals that release the milk to the milk ducts so that it can start to come out of the nipples.

This mechanism is important for breastfeeding or expressing milk, but it can also happen at other times. For instance, it can happen when a female hears their baby crying or even thinks about their baby. It can also sometimes happen when another baby cries.

11. Bumps on the areolae are normal.

The small bumps on areolae are also known as the Montgomery glands.

These glands secrete oil to cleanse the nipple opening and prevent the chapping and cracking of the nipple that often occurs due to breastfeeding.

According to an older study, there is also evidence to suggest that this secretion may attract newborns to the nipples.

Although these bumps are normal, a person should see a doctor if they become inflamed or secrete brown fluid.

12. Breast milk can come out of multiple places.

There are between 10 and 20 perforations in the skin of the nipples, called nipple pores, from which the milk exits the body.

When breast milk is pumped, it can either look like a single stream or be visibly coming from different “holes” in the nipple.

13. Nipples can change shape during pregnancy.

One study demonstrated that during pregnancy, nipple length and width, as well as areola width, could increase significantly.

However, if a person notices that their nipples have changed drastically, and they are not pregnant, it is important that they visit their doctor.

The Centers for Disease Control and Prevention (CDC) advise that changes to the nipples could be a sign of breast cancer.

14. Nipple cancer is a rare form of cancer, but it can happen.

Nipple cancer, also known as Paget’s disease, is a rare condition associated with breast cancer. It affects the nipple and the areola.

According to the National Cancer Institute, about 1–4% of breast cancer cases involve Paget’s disease.

This condition can also affect males, but it is much more common among females.

Although doctors do not entirely understand what causes Paget’s disease of the breast, they do have theories.

The most widely accepted theory is that cancer cells from a tumor inside the breast travel through the milk ducts to the nipple and areola. This theory would explain why this cancer is so rare in males.

15. People can get nipple tattoos.

During a mastectomy, the surgeon may sometimes need to remove the nipple too.

After undergoing this procedure, some people may opt for nipple reconstruction. The options include using a nipple prosthetic, a skin graft, or a tattoo.

16. Nipple stimulation can induce labor.

Stimulating the nipples may help the onset of labor.

According to a 2018 study, oxytocin can help induce labor. Nipple stimulation produces oxytocin.

In the same study, 3 days of breast stimulation caused oxytocin levels to increase.

Other research has shown that nipple stimulation can also have an effect on the duration of labor. A 2015 study found that stimulating the nipples during labor shortened the first stage of labor to an average of 3.8 hours.

Learn more about nipple stimulation and labor here.

Nipples can be a good indication of a person’s health.

Although many factors can affect the nipples, if a person notices any discharge or changes in this part of the body, they should see a doctor.