Until he met his wife, Trumbo, a sports instructor, had spent time with kids and liked them but rarely thought of having any. Now he looks forward to teaching his son what he's taught so many others.
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But for reasons both social and scientific, men may soon be worrying about a good deal more. Last August, a study in Nature found that older fathers face a significantly increased risk of siring a child with autism or schizophrenia, with mutations in sperm that may contribute to these conditions doubling for every 16.5 years a man ages. That paper followed an April 2012 study, also in Nature, that found older fathers are four times as likely as mothers to pass on autism-related genetic glitches, with the risk becoming especially acute after men turn just 35--precisely the age at which the ostensibly more-fragile female reproductive system is said to enter the danger zone. Between those two reports came a May study in the American Journal of Men's Health linking a father's age to preterm birth, low birth weight and stillbirth. These and other papers, some showing possible links between older dads and the occurrence of cleft palates and certain cancers, are leading to the inescapable conclusion that late fatherhood isn't just the amusing indulgence of an old man with a willing young wife but also a true health peril for kids, perhaps worse than those caused by an older mom.
"The biological clock was always there for me," says Antoinette Vitale, 47, a former CPA and now a full-time mother living in Westchester County in New York. Vitale had her three children when she was 38, 40 and 42--the age range at which doctors and well-meaning relatives start sounding alarms. Her husband, who's a year older, was spared such procreative prodding. The next generation of fathers may not have it so easy. "Men haven't paid much attention to their biological clocks," says Newman, "and now they have to."
Fragile Sperm
There were many reasons the August study linking paternal age with autism and schizophrenia caused such a stir; one was that it defied expectations. Sperm have a reputation for hardiness simply because they're produced in such millions-strong abundance. But plentiful sperm are not the same as fit sperm--and here, a woman's ovum has a very big edge.
Baby girls are believed to be born with all the eggs they'll ever have. Sperm, on the other hand, must be produced anew constantly and divide, on average, every 16 days. Since there are a great many 16-day stretches in a man's life and every division represents a chance for a genetic copying error, sperm can accumulate a lot of what are called de novo mutations. On average, a 20-year-old male passes 15 to 25 such genetic typos on to any child he fathers; for a 45-year-old, the figure is 65. Mothers, no matter how old they are, pass along only about 15.