Women have long been made aware, sometimes painfully, of their dwindling fertility and the increased risks that come with waiting until their 30s and 40s to have children. But aging men should worry, too, says Jennifer Vanderbes in The Wall Street Journal. While it's long been assumed that men can father children well into their twilight years without consequences, it turns out that "men are also at the mercy of age when it comes to having kids." Researchers have found that men over 40 are far more likely to father children with birth defects, autism, and a greater likelihood of developing some cancers and mental illnesses. Here, an excerpt:

Older fathers made headlines several years ago when researchers at the Mount Sinai School of Medicine reported that a man over 40 is almost six times as likely as a man under 30 to father an autistic child. Since then, research has shown that a man's chances of fathering offspring with schizophrenia double when he hits 40 and triple at age 50. The incidence of bipolarity, epilepsy, prostate cancer and breast cancer also increases in children born to men approaching 40. ...

Of course, "nobody likes to think that they're aging," says Dr. [Harry] Fisch. "Certainly men. They were on the throne, they were the kings: 'We don't age, we stay fertile longer than women, we can have babies into our 90s....' Men live in denial."

Read the entire article in The Wall Street Journal.