Bad news for men with semen, sperm issues. New research has found that they may have a greater risk of dying. The study, led by a researcher at the Stanford University School of Medicine, discovered that men with multiple defects in their semen were more than twice as likely to die over a eight-year period as men who had normal semen. The findings are published in Human Reproduction.

Michael Eisenberg, MD, PhD, assistant professor of urology at Stanford, and his colleagues examined data on approximately 12,000 men, ages 20 to 50, who had sought evaluation for possible infertility at one of two infertility centers. The researchers were able to look at several indicators of a patient’s semen quality, including total semen volume, sperm counts, motility and shape.

“We were able to determine with better than 90 percent accuracy who died during that [eight-year] follow-up time,” Eisenberg said in a statement. “There was an inverse relationship. In the years following their evaluation, men with poor semen quality had more than double the mortality rate of those who didn’t.”

Although only 69 of the nearly 12,000 men died during the follow-up period, the researchers explain that this likely reflects the patients’ relative youth and their higher-than-average socio-economic status, which gives them access to healthier food, better education and health care.

Why exactly sperm defects raise the risk of dying is still unknown to researchers.

“Could it be genetic, developmental or hormonal factors?” Eisenberg wondered. “Or could it be that something about the experience of having and raising kids — even though you may sometimes feel like they’re killing you — actually lowers mortality?”