Have you noticed that some people have tiny, visible holes above their ears. No, I'm not talking about piercings or some body modification. These holes have been there since birth and are a natural mutation. It also doesn't mean that these people will star in the next X-Men film either.

A small segment of the population are born with this difference called preauricular sinus. In the US, under one percent of the population have them, in parts of Asia and Africa around 4-10% of people may be affected.

Technically a birth defect, it was first documented in 1864 by Van Heusinger. It is believed by some that it was part of our evolution.

Usually these dimples don't cause any health problems, however should the sinus become infected or form a cyst, treatment may be necessary. This involves either draining the sinus or removing it completely.

Often preauricular sinuses are passed down through generations. It can occur on just one ear or both, but research has suggested that it's most common on the right side.

Do you have this unique difference?