Very few men outlive their own fertility.
Kids are at the center of marriage, argue supporters of California’s same-sex marriage ban. But infertile opposite-sex couples can get married, opponents point out — so why not same-sex pairs? Men stay fertile till their deathbeds, said an attorney arguing against rights for same-sex couples. Confused? Consider the actual debate before the Supreme Court on March 26, 2013, in Hollingsworth vs. Perry. Justice Elena Kagan compared a ban on marriage licenses for couples over age 55 with a ban on marriage licenses for same-sex couples. Couples over 55 are unlikely to produce children, she pointed out. Yet it would be unconstitutional to deny them a marriage license. So, she asked, what’s the difference between that couple and a same-sex couple that can’t naturally conceive? Attorney Charles Cooper, arguing in favor of California’s ban, said, "With respect to couples over the age of 55, it is very rare that … both parties to the couple are infertile." A bit later, he clarified: "Very few men outlive their own fertility." He explained that the state’s interest in marriage extends to older couples, because preserving the "marital norm" — with its obligations of fidelity and monogamy — discourages "irresponsible procreative conduct outside of that marriage." (He meant old guys having affairs with young mistresses.) It’s settled science that most women over 55 can’t naturally conceive. But we wondered — apart from what it may mean for the constitutionality of same-sex marriage — what does science say about men’s fertility in their declining years? Do "very few men outlive their own fertility"? What studies say — and don’t say We spoke with a range of fertility experts, combed through their research, and can tell you this: Science doesn't yet tell us how many old men can make babies. Especially if we’re talking about natural conception of the variety that might take place if a 70-year-old is seeing a 25-year-old on the side. The kind that requires, you know, sex, and enough sperm that move vigorously enough to reach and penetrate an egg. (One expert told us some couples who visit fertility clinics don’t realize sex is required to make babies. We’re going to assume here that you generally get how this process works.) We do know that roughly 10 to 20 percent of couples generally are infertile, with the man’s fertility a factor in about 40 percent of those cases. But evidence is tricky when it comes to fertility as men age. Cooper’s office sent us links to two studies that note men make sperm late into life. But one happens to document age-related decline in sperm quality and the other notes that studies suggest men contribute to reduced fertility beginning in their early 40s. Here’s a roundup of points on both sides. Signs of late-life fertility: • There’s no "cliff" as with menopause around age 50 in women, where fertility drops off dramatically. • Most men still make sperm into old age, studies say. (This is different from women, who are born with all the eggs they will ever have — no making fresh ones.) • Sperm count, one of the most important measures of male fertility, isn’t as sensitive to age as other factors, said Andrew La Barbera, scientific director for the American Society for Reproductive Medicine. • We’ve all heard of guys old enough to be great-grandfathers fathering kids. Or, as Justice Antonin Scalia joked in court, about the late Sen. Strom Thurmond of South Carolina, who fathered four children in his late 60s and early 70s. Points that give pause: • While there’s no menopause-like fertility cliff for men, sperm quality, amount of semen and fertility do appear to decline with age. Older men may be more likely to make sperm that’s strangely shaped and doesn’t swim well. "These data suggest that men may become progressively less fertile as they age," said a 2003 study cited by Cooper’s office. • The timing of fertility decline may vary dramatically from person to person — but there’s a need for more research to explain the variation. • There’s no clear research that shows how many older men may be capable of impregnating a woman in a year of regular sex, the clinical definition of fertility. "We don’t have data on men as they age ... not men who are in their 60s and 70s," said Harry Fisch, clinical professor of urology and reproductive medicine at Weill Cornell Medical College and author of The Male Biological Clock. "Very few men in these studies are older." "If it’s true, then let me ask you: Where’s the data?" That point was echoed by researchers who explained the limits of current studies. "It is rather difficult to give a precise estimate of (men’s) fertility by age because very few are still trying to have children beyond 60 or 65 years," said Henri Leridon, an expert in human reproduction who headed research at France’s National Institute for Demographic Studies. An Israeli fertility researcher, Eliezer Girsh, told PolitiFact that not only does fertility decline in men after age 50, but that just 20 to 40 percent of men are "still fertile in advanced age." Other experts said that, frankly, there’s a need for more research. But anecdotes sometimes overshadow the lack of data. The oldest scientifically documented case of fatherhood: a 94-year-old. Our ruling Cooper argued before the Supreme Court that "very few men outlive their own fertility." Experts we consulted generally agree that men — or at least some men — may still father children well into their advanced years. But whether that’s most men or a minority isn’t yet supported by research. Meanwhile, emerging studies document declining fertility as individual men age, and studies don’t yet confirm how many men remain fertile their entire lives. Given the sweeping nature of Cooper's claim, and the lack of unequivocal evidence, we rate it Half True.
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