DEAR DR. DONOHUE: I have a handsome, 17-year-old grandson who is going bald. My daughter-in-law tells me it’s hereditary. Her father was bald at an early age. I don’t buy that.

It is not unusual for my grandson to shampoo his hair twice a day. I think that exacerbates his problem. Would you recommend hair transplants? – C.S.

ANSWER: Will you buy the undisputed fact that genes do have a great influence on hair loss? They really do. However, it is impossible to cite a bald relative and predict that other family members are going to meet the same fate. And it is not true that baldness comes from the mother’s side of the family only. The baldness gene or genes come from either side.

Hair loss has to do with the action of male hormones on hair follicles. Men begin to lose their hair between the ages of 17 and 40, thanks to these hormones. By age 50, nearly half of them have noticeable thinning, and not a few are bald. Twice-a-day shampooing doesn’t exacerbate hair loss.

Admittedly, 17 is young to have a significant hair-loss problem. What to do about it is something that is best left to the young man. If it doesn’t bother him, then let matters be.

If it does bother him, he has a number of options. There are two medicines approved to slow hair loss and restore some hair growth. Minoxidil can be obtained without a prescription. It’s a liquid applied to the scalp. Finasteride is a pill that requires a prescription. It is the same medicine that’s used to shrink enlarged prostate glands. The dose used for hair restoration is much smaller than the dose for prostate shrinkage. Both medicines are lifelong commitments. Seventeen is quite young to commit to a lifetime of medicine use. If the medicines are stopped, hair begins to fall out again.

Hair transplantation is another option. That too can be done later if he wishes.

On the outside chance that an illness is at work here, it would be worthwhile for the young man to see the family doctor.

DEAR DR. DONOHUE: You explained how a vein taken from the leg can replace a heart artery in a bypass operation, but you didn’t explain how the leg can function without that vein. Nature gave us that vein, and it must have an important use. Please explain. – J.C.

ANSWER: Nature gave us many leg veins. The others take over admirably for the one that’s removed for a heart-artery graft.

Surgeons can also use an arm artery for such grafts.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475.