What’s that ticking sound? If Harry Fisch, M.D., director of the Male Reproductive Center at Columbia-Presbyterian Medical Center in New York City, is right, it could just be your male biological clock keeping time.
Indeed, Dr. Fisch says that men in their mid-to-late 30s often see a sharp increase in the incidence of genetic defects in their sperm, proportionally increasing the risk of severe birth defects in their children. Conceive asked Dr. Fisch a few questions about the claims made in his book The Male Biological Clock (Free Press, 2005).
How likely is a man to have fertility problems or genetic defects in his sperm once he passes the age of 35?
It depends. Some men have a quicker clock than others. A study of couples who took longer than 12 months to instigate pregnancy found that men over 35 were twice as likely to be infertile as men under 35. That study was for couples who actually managed to conceive – so rates of infertility among men over 35 are probably higher than that study suggests. As for the risk of birth defects, we don’t know exactly when that risk starts or how severe it is. We do know that children fathered by men in their 40s and 50s have double the risk of schizophrenia compared to children born to younger fathers. Men over the age of 35 have a greater risk of fathering children with Down Syndrome, but only if the mother is also at risk (i.e. over the age of 35).
We studied Down Syndrome because it is one of the most common genetic abnormalities, but we wonder if it’s the canary in the mineshaft. What other problems are we missing that we don’t know about? As more and more couples over 35 have children, this may become a public health concern.
Is The Male Biological Clock a wake-up call for men?
I would tell my own children to consider having children before they reach age 35, but we know that many couples over 35 are trying to have children. One thing I would tell those older couples is to look for underlying problems in the male. Because women are the ones who have babies, a lot of men are overlooked when treating infertility, but a woman’s fertility can often be improved by treating the male. For example, if a man has a prostate infection, that can affect his fertility, and as men get older, they more commonly have urologic problems.