Despite the fact we all have them, somehow we're all a bit fascinated by the tiny pigmented areas of skin known as nipples. But sexualization aside, nipples actually serve an essential evolutionary purpose of feeding babies. So for the 99% of us who aren't currently breastfeeding, and for the 50% of us who never will, their purpose is often called into question.
We shed some light on the matter:
1. Chandler's third nipple isn't so weird after all
It's actually perfectly normal to have more than two nipples. Some notable personalities with extra nipples include Lily Allen who apaprently has three, and Harry Styles, who's reported to proudly boast about having four of them.
2. Why do men have them?
With no biological purpose to men's nipples, it makes you wonder why they still have them. It's because all embryos actually begin to grow as females, and it's not until after nipple development that fetuses with the male Y-chromosome differentiate into boys, while embryos with the X chromosome develop into girls.
3. Nipple piercings aren't bad for you
From a medical perspective, so long as the piercing is performed hygienically, with sterile equipment, there's little risk of problems. Be warned though; nipple piercings can take several months to fully heal. Piercings also shouldn't have any effect on a woman's ability to breastfeed in the future, providing the piercing has sufficiently healed. From a style perspective, Kendall Jenner might rock the look, but each to their own!
4. Erection issues
Nipples contain super sensitive nerves, which react to various stimuli such as cold temperatures and touch. This happens automatically, as the muscles around the breast tissue contract, causing the nipple to become erect. This can also occur as the result of emotive states such as fear or the obvious: sexual arousal.
5. There's no "right color"
As with every other part of the human body, nipples come in a plethora of different shapes, sizes, and colors. Nipples also change color during pregnancy, where they often become darker. Some nipple changes can be a concern, however, with regard to breast cancer. Signs to look out for include discharge, rashes, or a change in position such as inversion.
6. Sensitivity: the smaller, the better
A recent study found that smaller breasts are often more sensitive than bigger ones, because the nerves are more concentrated. The same goes for nipples: smaller nipples, denser nerves, more sensitivity. Breast enhancement surgery will also usually cause loss of sensation around the nipple, although this is more potentially associated with nerve damage during surgery.
7. You can get innies or outies
Like with our belly buttons, inverted nipples are perfectly normal and are present from birth in many people. Some people choose to get this "fixed" by surgery, although this is medically unnecessary and simply for aesthetic reasons. A newly inverted nipple, however, may be cause for investigation, and could be a sign of breast cancer.
8. Those tiny hairs are normal too
It's just the same as having tiny hairs everywhere else on our bodies: completely normal. It's thanks to the hair follicles we've got in the area. The only health issue associated with nipple hair is polycystic ovary syndrome, but this likely won't be the only symptom anyway. If you're particularly distressed about its presence, however, your best bet is probably tweezers. We beg of you, steer clear of hair removal cream. It'll BURN.
9. Nipples can get infected
When breastfeeding, a build-up of milk in the milk ducts can get infected with bacteria. This is known as infective mastitis, and symptoms include nipple discharge, pain when breastfeeding, and a burning pain in the breast. These symptoms can also be the result of damage to the nipple, such after nipple piercings.
10. Everyone has those tiny bumps on the nipple
Don't panic, these are perfectly normal. Known as areolar glands, these are simply sebaceous glands and are found all over the skin, especially on the face and scalp. They release oily secretions to lubricate and protect the skin, in this case of the nipple and surrounding areola, keeping it soft and smooth.
All nipple-knowledge kindly provided by Dr Seth Rankin, founder of London Doctors Clinic.
Follow Cat on Twitter.
This article originally appeared on Cosmopolitan.co.uk. Minor edits have been made by the Cosmo.ph editors.