Report: Men Large Part of US Infertility Problem

Men are a large part of the infertility problem in the U.S., and experts are baffled by it, Newsweek reported Tuesday.

"Reproduction may be the most important function of any species," said Hebrew University public health researcher Hagai Levine. "Something is very wrong with men."

Men are either the sole or contributing cause in about 40 percent of cases in infertility, according to the American Society for Reproductive Medicine, and male fertility gradually degrades around the mid-30s.

Work by Levine and Shanna Swan, a professor of environmental medicine and public health at the Icahn School of Medicine at Mount Sinai, also found sperm levels have fallen by 52 percent among men in Western countries between 1973 and 2011. The decline has continued to grow, and fertility rates have drastically dropped in the same countries.

"This is pretty scary," Swan said. "I think we should be very concerned about this trend."

In order to keep a country's population stable through birth alone, women need to average about 2.1 children, but the U.S. is at 1.8.

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