From The New York Times:
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. A number of studies suggest that male fertility may diminish with age.
It’s a touchy subject. “Advanced maternal age” is formally defined: women who are 35 or older when they deliver their baby may have “A.M.A.” stamped on their medical files to call attention to the higher risks they face. But the concept of “advanced paternal age” is murky. “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,” Dr. Sokol said. But by and large, she added, “the sperm can still do their job.”
“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.’ “
More here.