Gray hair is nothing to be ashamed of. In fact, according to a new study by researchers in Japan, the presence of gray hair may be a good sign that your body is naturally protecting itself from cancer.

A series of mouse experiments suggests we've evolved to let go of cells that are at risk of generating tumors at the expense of a little color.

Our cells are routinely subjected to a barrage of 'genotoxic insults,' or DNA damage wrought by a wide variety of environmental factors. Skin cells bear the brunt of many such affronts, given their role in helping buffer our internal organs from the outside world.

DNA damage can contribute to cell aging as well as to the development of cancer, although the specific genotoxins, signals, and cellular mechanisms involved with the physical signs of aging remain poorly understood.

The new study focuses specifically on melanoma, a type of cancer predominantly found in the skin, where it originates in melanocytes – specialized skin cells that generate melanin, the pigment responsible for skin and hair color.