Men’s ability to father children in a timely manner may be affected by certain chemicals in sunscreens designed to protect against ultraviolet rays, according to recent study findings published in the American Journal of Epidemiology.

“In our study, male fecundity seems to be more susceptible to these chemicals than female fecundity,” Germaine Louis, PhD, director of the division of intramural population health research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in a press release. “The women participants actually had greater exposure to the UV filters overall, but their exposure wasn’t associated with any significant pregnancy delays. Our next step is to figure out how these particular chemicals may be affecting couple fecundity or time to pregnancy — whether it’s by diminishing sperm quality or inhibiting reproduction some other way.”

Germaine Louis

Louis and colleagues evaluated 501 couples (women aged 18 to 44 years; men aged ≥18 years) trying to conceive a child to determine if benzophenone (BP)-type UV filters affectedfertility.

Participants were followed until pregnancy or 1 year of trying to determine how long it took women to get pregnant. Urine samples were also tested to measure concentrations of five UV filters including 2,4-dihydroxybenzophenone (BP-1), 2,2,’4,4’-tetrahydroxybenzophenone (BP-2), 2-hydroxy-4-methoxybenzophenone (BP-3) 2-2’-dihydroxy-4-methoxybenzophenone (BP-8) and 4-hydroxybenzophenone; all are associated with endocrine-disrupting activity.

Researchers found that BP-2 (fecundability OR=0.69; 95% CI, 0.5-0.95) and 4-hydroxybenzophenone (FOR=0.74; 95% CI, 0.54-1) were associated with reduced fecundity in males.

Following adjustment for the couples’ concentrations, male BP-2 concentration was still associated with reduced fecundity (FOR=0.69; 95% CI, 0.49-0.97).

“The skin is the body’s largest organ, and how we care for skin matters in more ways than one,” Louis said. “Sunscreen is important for sun protection, and we definitely encourage people to continue using sunscreen to avoid skin cancer. But men who are concerned about fertility may be interested in other ways to reduce their exposure to benzophenone UV filters — whether by cutting back on other products that contain the UV filters or by washing after returning indoors.”