As fathers age, the risk of abnormal offspring may rise.
When it comes to fertility and the prospect of having normal babies, it has always been assumed that men have no biological clock — that unlike women, they can have it all, at any age.
But mounting evidence is raising questions about that assumption, suggesting that as men get older, they face an increased risk of fathering children with abnormalities. Several recent studies are starting to persuade many doctors that men should not be too cavalier about postponing marriage and children.
Until now, the problems known to occur more often with advanced paternal age were so rare they received scant public attention. The newer studies were alarming because they found higher rates of more common conditions — including autism and schizophrenia — in offspring born to men in their middle and late 40s. A number of studies also suggest that male fertility may diminish with age.
"Obviously there is a difference between men and women; women simply can't have children after a certain age," said Dr. Harry Fisch, director of the Male Reproductive Center at New York-Presbyterian Hospital/Columbia University Medical Center and the author of The Male Biological Clock.
"But not every man can be guaranteed that everything's going to be fine," Fisch said. "Fertility will drop for some men, others will maintain their fertility but not to the same degree, and there is an increased risk of genetic abnormalities."
It's a touchy subject. "Advanced maternal age" is formally defined: women who are 35 or older when they deliver their baby may have "AMA" stamped on their medical files to call attention to the higher risks they face. But the concept of "advanced paternal age" is murky. Many experts are skeptical about the latest findings, and doctors appear to be in no rush to set age guidelines or safety perimeters for would-be fathers, content instead to issue vague sooner-rather-than-later warnings.
"The problem is that the data is very sparse right now," said Larry Lipschultz, a specialist in the field of male infertility and a past president of the American Society for Reproductive Medicine. "I don't think there's a consensus of what patients should be warned about."
And many men maintain their fertility, said Rebecca Sokol, president of the Society of Male Reproduction and Urology.
"If you look at males over 50 or 40, yes, there is a decline in the number of sperm being produced, and there may be a decline in the amount of testosterone," Sokol said. But by and large, she added, "the sperm can still do their job."
Some advocates welcome the attention being paid to the issue of male fertility, saying it is long overdue and adding that it could level the playing field between men and women in the premarital dating game.
"The message to men is: 'Wake up and smell the java,'" said Pamela Madsen, executive director of the American Fertility Association, a national education and advocacy group. "It's not just about women anymore, it's about you too. It takes two to make a baby, and men who one day want to become fathers need to wake up, read what's out there and take responsibility."
Analyses of sperm samples from healthy men have found changes as men age, including increased fragmentation of DNA, and some studies outside the US have noted increased rates of some cancers in children of older fathers.
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