article

11.07.11

How Old Is 'Too Old' for Fatherhood?

Women aren’t the only ones who stress about their biological clock—men face similar anxieties over becoming older dads, reports Sarah Wildman. Some may even turn to sperm freezing.

Alexander is, on paper and otherwise, a success. He has degrees from two Ivy League schools. He runs his own consulting business, with offices in Boston and Washington, D.C. And at 38, he’s got a beautiful 29-year-old girlfriend with whom he’s quite happy. But the truth is her age is a sticking point. She’s also an entrepreneur, with a business that’s just getting started. She’s got no interest in starting a family any time soon. She’s got time.

The problem is, Alexander wants to be a dad. Badly. He sees fatherhood as the missing link, the key to full happiness. So Alexander (not his real name) finds himself in the unique position of commiserating with his women friends who’ve yet to find partners, or whose spouses are dragging their feet on kids. “Ideally,” he says with a sigh, “I’d have a family already.”

For decades, the age of parents has steadily crept northward, with women bearing the brunt of our collective social and scientific anxiety. We endlessly wring our hands over how old is “too old” to be a mother, and we obsess over the quality and fragility of our egg supply. The recent New York magazine story Parents of a Certain Age, which looked at mothers carrying babies well into their early 50s, tapped directly into these concerns, featuring a takeoff of that famous Annie Leibovitz photograph of resplendent, nude Demi Moore—yet this time the cover model was naked, pregnant, and distinctly grandmotherly.

But let’s face it: it’s not just mothers who are getting older, and it’s not just women who fret over the perfect age to start a family, or who face fertility problems and birth complications. It’s men too. The biological clock exists for all of us.

“There are several reasons I’m concerned,” says Alexander, explaining his own mounting stress. “One reason is social. As my friends started to have kids, well, the socialization patterns are dictated by children, and if you don’t have kids of the same age it’s hard to hang out; it’s hard to be on the same schedule."

He says he’s also anxious about longevity, given that his dad died at 66. “Just from a mortality perspective,” he’d like to have a child soon. Then there’s his energy level, which he says he’s already seen go down. “You want to play with your kids, and as you get older it's hard to necessarily do that—and you might not have the same vivacity to run around for a few hours that you might have had when you were younger.”

Many men think such worry is somewhat overblown; after all, Pablo Picasso had his last kid in his 70s, and theoretically—look at eight-times-a-charm Rod Stewart!—men can father forever. Even guys who profess not to want to wait forever still take comfort in the idea that they don’t really have to hurry up. “I don’t want to be an old dad,” says David (not his real name), a D.C.-area lawyer who’s also 38, but he tends to date younger because he’s not “quite ready” to start the path to diaper changing.

Over the last several years, however, evidence has mounted that the reasons Alexander should worry, and David might want to reconsider, are not just social. What doctors call the “paternal age effect”—a condition that affects the children of men older than 35, and especially after 40—may lead to an increased incidence of all sorts of serious problems like dwarfism, Marfan syndrome (a connective-tissue disorder), and Apert syndrome (in which the skull and other body parts are malformed). “Men should be cognizant that they are at some increased risk for having children with various disorders,” says Ethylin Jabs, professor of developmental and regenerative biology at Mount Sinai School of Medicine. Indeed, there has also been some association between advanced paternal age and an increased incidence of schizophrenia and autism, as well as diminished intelligence. 

“Sperm is made like any cell in the body,” says Jabs. “Your DNA is replicated, and then the cell splits into two new cells, so this process of spermatogenesis creates new sperm, there is ongoing replication of DNA … With each ejaculate, men make millions of new sperm, but as they grow old the machinery that allows this process to occur isn’t as effective as it was when they were young. It doesn’t work as well. So errors get introduced.” And those errors—called point mutations—can create a fetus with abnormalities.

If all that weren’t enough to frighten men into fatherhood, there’s more new evidence that the myth of the man-who-can-father-forever may be exactly that: a myth. A new study presented just last month by the National Foundation for Fertility Research at the American Society of Reproductive Medicine annual meeting in Florida showed that men after 40 are—just like women—increasingly less fertile. In fact, the lead scientist on the study, Mandy Katz-Jaffe, says, bluntly, that men who are 35 and not yet partnered should consider freezing their sperm.

The premise of the study was to determine whether a male biological clock exists; since following humans would “take 60 years,” they relied on a mouse model. Using pubescent, teenage, fertile male mice, the scientists mated the boys with three to five young females each month, for months. The females were always young. The males were allowed to age “naturally”—in other words, they just lived their lives (with a lot of sex on the side).

“What we noticed was that up until 12 months old, which is midlife for these mice, they were absolutely fertile, with no variability in the babies, in the fetuses, in the time it took for them to conceive—everything was consistent. But once they hit 12 months—which is about 40 years old in humans—there was a dramatic deterioration on every parameter,” says Katz-Jaffe. 

If scientists like Mandy Katz-Jaffe have their way, healthy men will soon start freezing their sperm.

Not only did the mice’s ability to create a pregnancy “drop down to levels we would consider infertile,” but her team also saw “a drop in the quality of the embryos.” They found that “only 50 percent of the males were able to establish a pregnancy” at 12 months, “when, up until then, it had been 100 percent.” At 15 months, the human equivalent of 50 or so, the ability to create a pregnancy dropped to 10 percent.

“So, again, the question was ‘Do males have a biological clock?’” says Katz-Jaffe. “Is there an impact on pregnancy with aging sperm? And the answer is: absolutely. There is a huge impact on quality and potential for reproduction as sperm age.”

Echoing egg-freezing proselytizers, Katz-Jaffe gets earnest. “Men in their 30s can make a choice in regards to freezing their sperm because they haven’t met women of their dreams or their career [isn’t ready] or they don’t want children right now. Freezing sperm can improve their chances of having a healthy offspring when they do want to have children. It’s a lot easier for men to give a sperm sample [than for women to freeze eggs], and it’s a lot cheaper. It is an insurance policy. You might not need to cash it in, but you might.”

So far the only men who regularly freeze their sperm are those who face testicular cancer or other cancer treatments that might affect their sperm count or viability. But if scientists like Katz-Jaffe have their way, healthy men will soon approach sperm banks as well. 

Meanwhile, Alexander says he’s also heard that, as with women, his chance for fatherhood may diminish by the year. “So yes, add that to the list: fertility problems,” he says. So far he isn’t planning to do anything about it. But he’s worried.