As the years pass, so do the grays of our lives. (Groan, I know.) Yet some people, like Stacy London, have a streak of whitish hair on an otherwise solid mane. I wondered if that was a style choice, until on one episode of What Not To Wear, Stacy explained that she's had it since she was a child.

Curious why this happens? Learn about it when you


Hair color is controlled by several different genes, each contributing to the pigment color. In addition, the genes determine the color's concentration in the hair shaft. If a patch of skin had a somatic mutation, it could inactivate one or more genes that control the pigment deposition, leaving a lighter patch of skin on her scalp similar to a birthmark. The patch will remain pale and can also result in a paler, or different, color hair growing out of it. There you go.