Theories of origin of preauricular sinus (also known as a congenital auricular fistula) includes: defective or incomplete fusion of the beginnings of the external ears at the embryonic stage. Just one third of folks even know they have one.
The sinus may be bilateral (both ears) in 25-50% of cases, and bilateral sinuses are more likely to be hereditary. In unilateral cases, the left side is more commonly affected. They are usually benign and do not change through life.
On Facebook, people with a preauricular sinus believe they are special. Neil Shubin, an evolutionary biologist, has a highly speculative theory that the holes could be an "evolutionary remnant of fish gills."
In Taiwan, the incidence of preauricular sinuses is estimated to be 1.6-2.5%; in Scotland, 0.06%; and in Hungary, 0.47%. In some parts of Asia and Africa, the incidence is estimated to be 4-10%. Just 0.1 percent of the population have it in the US, and 0.9 percent in the UK. Bottom line, I always knew I was special, now I can prove it. Ha