These days more women are having babies into their 40s, but the idea that women are facing down the biological clock is pretty pervasive—once you’re over 35, you automatically receive that “advanced maternal age” classification, while your male partner’s age may never even be mentioned. The pressure on older moms is unfair, because according to new research from Rutgers University, men may face age-related fertility decline too and America’s dads are getting older.

It’s a new idea, but this finding actually takes 40 years worth of research into account—which, coincidentally, is around the age male fertility may start to decline. According to Rutgers researchers, the medical community hasn’t quite pinpointed the onset of advanced age, but it hovers somewhere between ages 35 and 45.

The study which appears in the journal Maturitas, finds that a father’s age may not just affect his fertility, but also the health of his partner and offspring.

Based on previously conducted research, the team behind this study found evidence that men over 45 could put their partners at greater risk for pregnancy complications like gestational diabetes and preeclampsia. Babies born to older fathers also have an increased likelihood of premature birth, late stillbirth, low Apgar scores, low birthweight, newborn seizures and more. The risks appear to exist later in life, too: Research suggests children of older fathers have greater risk of childhood cancers, cognitive issues and autism.

There’s been plenty of studies surrounding advanced maternal age, but research on advanced paternal age is pretty slim—scientists don’t quite understand how age correlates to these factors at this point. But researchers from Rutgers believe that age-related decline in testosterone and sperm quality degradation may be to blame. “Just as people lose muscle strength, flexibility and endurance with age, in men, sperm also tend to lose ‘fitness’ over the life cycle,” Gloria Bachmann, director of the Women’s Health Institute at Rutgers Robert Wood Johnson Medical School, explains in a release for this news.

As we’ve previously reported, more and more men are waiting until later in life to have children. According to a 2017 Stanford study, children born to fathers over 40 represent 9% of U.S. births, and the average age of first-time fathers has climbed by three-and-a-half years over the past four decades —so this research matters now more than ever, and it may represent the first step towards setting certain standards in place for men who choose to delay parenthood.

The biggest thing to come out of this research may be the need for more awareness surrounding advanced paternal age. This particular study’s authors believe doctors should be starting to have conversations with their male patients, possibly even encouraging them to consider banking sperm if they’re considering parenthood later in life.

Women certainly tend to be aware of the age-related risks to their fertility, and many regularly hear that they should freeze their eggs if they’re not ready for motherhood. And while it’s still too early to say whether we’ll ever examine paternal age this closely, this research may set a whole new conversation in motion.

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