DEAR DR. DONOHUE: I have heard that married couples who have children later in life are more likely to have a child with Down syndrome.

Do you think that the highly advertised Viagra and other such potency enhancers could add to this problem? — J.B.

ANSWER: We have 23 pairs of chromosomes, 46 chromosomes in total. They’re long strands of genes. The ovum and sperm have only 23 single chromosomes — no pairs. This allows the mother and father to donate equally half of the baby’s chromosomes and genes.

In Down syndrome there’s an extra No. 21 gene. The Down infant has three No. 21 genes, a condition called trisomy.

The chances for a baby having Down syndrome increase with the mother’s age. Women older than 35 are more likely to have two No. 21 chromosomes in their ova. The older the woman is, the greater are the chances. For example, the chance that a woman of 30 years will have a Down baby are one in 1,000. The chances for a woman of 45 are one in 50.

Younger women, however, have more Down infants than older women. That sounds like a paradox. It isn’t. Younger women have many more babies than older women.

The father contributes to Down syndrome in only 5 percent of such children. Even though older fathers have a slightly greater risk of being the father of a Down baby, their overall role in the Down syndrome transmission is so minor that the total number of Down babies due to trisomy in sperm is quite small.

Viagra was introduced in 1998. I can’t substantiate that a greater number of Down children have been born since its introduction. You asked a very interesting question.

DEAR DR. DONOHUE: I am writing on behalf of several neighbors who have started soaking golden raisins in gin. Each of them takes nine such raisins a day. They claim this was a method shown on television to remedy arthritis. Have you ever heard of this? Our curiosity is getting the best of us. — E.G.

ANSWER: I have heard of this many times. No one has proven that it works. No reliable information suggests it might work. I don’t believe it’s a legitimate arthritis treatment.

However, if you like gin and like raisins, then the practice is OK, so long as you don’t go overboard on taking in too much alcohol.

The booklet on arthritis describes the different kinds of arthritis and their treatments. Readers can obtain a copy by writing: Dr. Donohue — No. 301, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./ $6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I have been diagnosed with mitral valve prolapse: “Mitral valve prolapse with mild regurgitation. Mild tricuspid regurgitation is present. Good ventricular function with ejection fraction of 60 percent.” Do I have any worry about these? Can calcium supplements be bad for the mitral valve prolapse? Are these conditions considered cardiovascular disease? — H.W.

ANSWER: Mitral valve prolapse, the valve between the upper left heart chamber and the lower left one, indicates that the valve balloons upward into the upper left chamber when the heart contracts. This isn’t a serious problem for most. Both the mitral valve regurgitation and the mitral regurgitation mean that these valves have an insignificant leak. These are not cardiovascular diseases. They’re cardiovascular conditions.

Your ejection fraction of 60 percent shows that your heart pumps like that of a young athlete.

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. Readers may also order health newsletters from www .rbmamall.com.