Surely you've seen for yourself the difference between innie and outie belly buttons. If you've never heard about inverted nipples, similar principles apply. Inverted nipples are turned inside out to varying degrees of severity. The biggest issue with inverted nipples is the idea that they're unusual, rare, and undesirable. We're here to tell you that they're none of these things!
First, 10 to 20 percent of women are born with them, making them a relatively common occurrence. If you think about it, that's far more common than people with naturally red hair, who make up only 2 percent of the population. In addition, they can become retracted over time due to weight loss, or in rarer cases, a disease affecting the breast tissue like cancer. Interestingly, inverted nipples may even be temporary for some women, and yes, men. It's also possible for one nipple to be inverted or not the other.