In the summer of 2024 fertility doctor Carrie Bedient sat across from a young couple and braced herself for a difficult conversation. The man and woman, both 32 years old, had been seeking medical help at her clinic to have a baby for the previous five years. But multiple rounds of in vitro fertilization (IVF) treatment had failed. By the time Bedient met with them to discuss the next steps, they had been through repeated miscarriages, failed embryo transfers and another kind of early pregnancy loss known as a chemical pregnancy.

Bedient, a reproductive endocrinologist at the Fertility Center of Las Vegas, had already ordered the usual battery of tests, including bloodwork, sperm count and motility tests and uterine anatomy exams. So she turned to what was then a more controversial idea: testing for DNA damage in the man’s sperm. He said yes.

By that point, a growing body of research had linked DNA fragmentation in sperm to an increased risk of miscarriage. But despite a test for this factor being available for some 15 years, it wasn’t commonly done—not least because doctors weren’t sure what people could do with the information. It was also unclear what caused the DNA damage in the first place; culprits ranged from environmental toxins to advanced paternal age to lifestyle factors, such as drug use and smoking. Plus, tests could cost up to $500 and wasn’t always covered by insurance.

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In the man’s case, the test results revealed a moderate level of DNA damage. Bedient gave him some frank advice on how to rehabilitate his sperm. “Hey, I need you to clean up everything you can,” she recalls telling him. He vowed to stop drinking alcohol, stop smoking, start exercising and take vitamin supplements—and it worked.

Six months later, the couple made another batch of embryos. “He completely turned everything around, and they’ve now got a beautiful baby boy,” Bedient says.

When a man starts male infertility treatment, he typically undergoes a workup that analyzes the volume and concentration of his semen, the shape of his sperm and those sperm’s ability to move. Yet the association of damaged sperm with miscarriage—in addition to newer research linking it to lower IVF live birth rates and poorer early embryo development—is pushing doctors to delve deeper into sperm health..

In its first update in 14 years, the American Society for Reproductive Medicine (ASRM) released new treatment guidelines for recurrent miscarriage, noting that testing for sperm DNA fragmentation “may be considered” in cases of multiple pregnancy losses. The guidelines stop short of outright recommending the tests; instead they say more research is needed to determine whether treatments for reducing sperm DNA fragmentation improve pregnancy outcomes.

But that is an important inclusion, says Clarisa Gracia, a reproductive endocrinologist at the University of Pennsylvania and chair of the ASRM practice committee that develops clinical guidance for fertility doctors.

“Our summary statement was hedging, but at least it spoke to the fact that the male evaluation is also important,” Gracia says. “If a couple is trying to get pregnant, I don’t think we should leave out the male, because we are learning more and more that male health affects reproductive outcomes as well.” The so-called male factor accounts for 20 percent of infertility cases and contributes to an additional 30 to 40 percent of cases in combination with female factors, according to the American Urological Association.

Fertility doctors didn’t even suspect that sperm played a critical role in miscarriage until just a few decades ago. Stories circulated in clinics about former female patients getting pregnant and giving birth after getting divorced and finding new partners. “I think anecdotally people had an inkling that there was something up related to the male in terms of miscarriages,” says Denny Sakkas, chief scientific officer at Boston IVF and IVI RMA North America, part of a global reproductive medicine group.

Sakkas conducted research in the 1990s that looked at the DNA of sperm from men with fertility problems and found little breaks in the molecules’ structure.

“DNA is like an instruction booklet. If there’s a lot of spelling mistakes in the DNA instruction, you might get a pregnancy,” he says. “But when the pregnancy gets to a certain stage where a particular spelling mistake will impact, say, the development of the heart tissue, the pregnancy won’t continue.”

Sakkas predicts that consensus will shift toward more proactively testing sperm in the case of repeat miscarriage, especially as companies offer increasingly sophisticated and lower-cost DNA testing. And doctors have more treatment options, including a new generation of sperm-sorting machines that can select the healthiest sperm to inject directly into an egg.

In the meantime, recognizing men’s role in miscarriage can help dismantle the stigma around pregnancy loss, says Brennan Peterson, a professor of marriage and family therapy at Chapman University.

“Masculinity is synonymous with virility, and I often hear from my clients, ‘If I can't have a child, then that means I am less of a man’,” he says. “There is a lot of shame, depression and secrecy. So for ASRM to put this out there hopefully will help the public understand that the pain of infertility and miscarriage are not solely women’s issues.”