Nov. 3, 2000 -- Men holding off on making a commitment to fatherhood could end up dealing with a diminished arsenal. The question is, does age matter for the gander like it does for the goose? You bet. Two studies released at a meeting of reproductive medicine specialists in San Diego show that age does affect sperm.
The first study, conducted jointly by Kentucky fertility experts at centers in Louisville and Lexington, found that sperm count diminishes steadily with age -- and quality goes down, as well. The researchers looked at four groups -- about 800 men in all from 20 to 60 years of age -- all of whom were undergoing fertility treatments with their partners. They found that sperm count dropped from about 107 million for men in their 20s to about 35.5 million for those in their 50s.
The second study, done by French researchers, seemed to partly answer the logical next question: What effect does this actually have on egg fertilization? In about 300 attempts at in vitro fertilization using donor eggs, they found a fertilization rate of about 60% in men less than 39 years old, with the rate falling to about 51% in those older than 39.
The message to women has been they're more likely to get pregnant at a younger age. For men, it's far less clear. "What we do know already is that ovarian aging very much affects the pregnancy rate," says Steven Sondheimer, MD, professor of obstetrics and gynecology at the University of Pennsylvania Medical Center. "In males, ... the studies probably don't translate as dramatically into a decrease in pregnancy rates."
Pamela Madsden of the American Infertility Association agrees that the onus is still on women. "It's not surprising that men's fertility declines as well. But I think it's still different than what happens with women. Their eggs deteriorate to the point of not being able to be fertilized. Between 40 and 44 for most women -- but even as early as 37 -- they may not ever be able to get pregnant again. And here you're talking about a reduction in count. We do have techniques today where we can take one sperm and insert it into a viable egg."
Still, Madsden says it's useful information because men can at least plan to keep what sperm they have as healthy as possible by not smoking or excessively drinking. "In my mind, the men are still the winners, because we've figured out that the issue with men tends to be the count."
But Larry I. Lipshultz, MD, professor of urology at Baylor College of Medicine in Houston, says a sperm evaluation study also was presented at the meeting, and it did not show a significant decline for older men.
All that aside, there's still the issue of quantity vs. quality, he says. "If sperm density is greater than 20 million with good quality and motility, you're not going to see an effect." Lipshultz points out that 20 million is the point between fertile and subfertile. But even then, it's not that simple. "You can't look [just] at numbers. They're the least important parameter. You have to look at quality.
"There's nothing new here," Lipshultz says. "[It's been] shown sperm counts do decline with age." But he says healthy men shouldn't worry about a decline to zero. "Men never stop producing sperm," he says.