How Sunblock Might Create Fertility Problems

It might be safe for her, but may not be for him. (Photo: SuperStock/Corbis)

Hot summer days are almost here, but a new Danish study suggests that men who reach for the sunscreen might have less of a chance of having children.

Researchers at the University of Copenhagen tested 29 of the 31 UV filters in sunblock that help keep out the sun’s harmful rays, and which are allowed in products in the U.S. and European Union.

“These results are of concern and might explain in part why unexplained fertility is so prevalent,” says Niels Skakkebaek, the study’s lead investigator and a professor at the University of Copenhagen in Denmark.

Live sperm cells taken from several healthy donors were exposed to the UV filters, and then the sperm cells were examined in a buffer solution made to mimic the environment of fallopian tubes.

Researchers honed in on calcium signaling inside the cells, which is essential to fertilization. They found that 13 of the 29 UV filters interrupted the process by changing the concentration of calcium ions.

The findings ultimately suggest that 45% of UV filters are endocrine disruptors that may hinder sperm’s healthy reproductive functions, say the researchers — who conclude that regulatory agencies should more closely study the effects of UV filters on fertility before approving them.

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However, a lead dermatologist disagrees with the findings, saying no conclusive evidence was presented, and he urged men to continue to slather on sunscreen to prevent skin cancer and signs of premature aging.

“Despite what may be observed when the chemicals are mixed directly with sperm at high levels, conditions in the real world when applying sunscreen to the skin are very different – minimal, if any, concentrations penetrate the skin into the blood stream, which translates to minimal exposures of the testicles to sunscreen,” Joshua Zeichner, MD, director of cosmetic and clinical research at Mount Sinai Hospital Department of Dermatology, tells Yahoo Beauty.

So what’s a man who wants strong sperm — but who doesn’t want to get skin cancer — left to do?

The Environmental Working Group (EWG), a nonprofit environmental research organization that scrutinizes ingredients in a cosmetic database, lists the natural physical UV filter of zinc oxide as completely safe (or a “0”) for reproductive health.

Familiar to most as the white stripe many lifeguards wear on their noses, zinc oxide fortunately now comes in more elegant sunscreen formulas that blend into skin and aren’t visibly white.

We suggest Badger Zinc Oxide Sunscreen Lotion SPF 25 ($18) or Kabana Organic Sunscreen SPF 32 ($18) for body, or Zeb’s Organics Sunscreen SPF 20 ($22) for face.

And for the little ones, All Good Kid’s Sunscreen SPF 33 ($16) combines certified organic ingredients in a gentle, hypoallergenic formula that dads can use, too.

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