American Idol winner Taylor Hicks sports a gray thatch and he’s only 29. CNN’s Anderson Cooper says he started to see salt mixed in with the pepper at age 20. Phil Donohue has used his striking white hair for decades to create an aura of eminence.

But take notice -- these are all men. Women, with the possible exception of household hinter Heloise and her long white mane, usually don’t flaunt the early gray look.

Why do some people go gray early? And does it have any health implications?

Graying Hair Yields Skin Cancer Clues

How Hair Works

Hair grows in stages, with a certain percentage of hair either growing or resting at any one time. The hair follicles -- the little bags under the skin where hair is formed out of skin -- also contain pigment called melanin.

When the body stops producing pigments, the hair becomes colorless, turning white. Mixed with darker hair, this produces a look most commonly associated with "gray." An actual gray hair may be a result of pigment dilution.

Why Start This Early?

“Premature graying is genetically determined for the most part,” David Bank, MD, tells WebMD. Bank is director of the Center for Dermatology, Cosmetic, and Laser Surgery in Mount Kisco, N.Y. “Graying is natural. We all do it eventually.”

When more than half the hair is white by age 40, though, this is considered “premature.”

Bank also points out that head hair grows more actively than body hair. So the head can go gray while other hairy parts remain your normal color. Correction: Your former color.

Basically, Bank says, if you look around your family and see a lot of gray, you may be headed in that direction.

What About Turning White Overnight?

A good scare, legend has it, can turn hair white overnight. Martyr Thomas More and the notorious Marie Antoinette supposedly went “white” the night before their executions.

What about Cooper? His new book, just out, titled A Memoir of War, Disasters, and Survival, recounts many harrowing adventures. Could his exploits have turned him white?

Of course, existing hair cannot “turn” any color because the part above the skin is already whatever color it is. One explanation for this “white overnight phenomenon,” is that the dark hairs suddenly fall victim to an autoimmune condition called alopecia areata, which can cause dark hairs to fall out overnight -- leaving the white ones.

Bank adds that the dark hair can fall out in quite large quantities in a short period of time and you might not notice. “I know that sounds weird,” he says, “but some goes down the drain. You may not notice.”

He also points out that going gray does not mean that your body’s aging process has speeded up. You aren’t suddenly going to lose function in other areas.

Links to Other Health Conditions

Premature graying has been associated with certain medical conditions such as thyroid disorders, vitiligo, vitamin B12 deficiency, and anemia. Vitiligo is an autoimmune condition in which the cells that make pigment (melanocytes) are destroyed, resulting in patches of hair and skin that become white.

There may also be a link with decreased bone mineral density in postmenopausal women, which is a risk factor for osteoporosis. In a study of 293 healthy postmenopausal women, those who had experienced premature graying of a majority of their hair by age 40 had decreased bone density throughout their bones compared with comparable women who did not have premature graying.

Can Anything Be Done?

With so many new lasers and dermatological treatments coming out these days, is there any way to stop or even reverse premature graying? Quartz Light rays have been mentioned, but Bank scoffs: “Yes, there have been attempts to stimulate color production. If this worked, though, don’t you think people would come flocking?”

Basically, people who stop plucking have no choice but the dye bottle -- or the bold grab for “distinguished” that Anderson Cooper, Phil Donohue, and Bill Clinton have championed.

Women usually reach for the dye bottle, not wanting to be “dated” by a society that disdains aging. If men take this route, they would do well to try a semipermanent dye at first. Make it one shade lighter than your natural color. If it is too light it won’t color.

Cooper also recommends keeping gray hair short and trim. If you grow it long, he has written, you look like a roadie for Peter, Paul, and Mary.

If you do decide to wear your gray with pride, you have the Bible on your side. “Gray hair is a crown of glory,” one proverb states. “It is gained in a righteous life.”

Of course, people lived to about 35 then and didn’t have as long to gaze upon their “glorious crown” of prematurely gray hair.

Star Lawrence is a medical journalist based in the Phoenix area, reviewed by Louise Chang, MD

SOURCES: David Bank, MD, director, Center for Dermatology, Cosmetic and Laser Surgery, Mount Kisco, N.Y. Mary Shomon, patient advocate; and author, Living Well With Graves and Hyperthyroidism.CNN.Com web site; “Going Gray,” by Anderson Cooper. WebMDAnswers to Questions: "Prematurely Graying: Usually No Cause for Alarm." WebMD Magazine: "Hair's the Problem." Dr. web site: "Sudden Graying of the Hair." Tobin, D.J. Exp Gerontol, January 2001; vol 36: pp 29-54. Orr-Walker, B.J. Journal of Clinical Endocrinology, November 1997; vol 82: pp 3580-3583.