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LISA NAPOLI: A study out in today's Human Reproduction Journal suggests pregnant women who eat a lot of beef might be affecting their sons' fertility. From the Health Desk at WGBH, Helen Palmer has more.
HELEN PALMER: This is what's called a retrospective study. Grown men provided a sperm sample, then asked their mothers what they ate when they were pregnant.
Men whose mothers ate beef more than once a day had a sperm count 24 percent below average.
SHANNA SWAN: The more beef meals the mother ate, on average, the lower was her son's sperm count.
Shanna Swan teaches gynecology at the University of Rochester. She suggests that growth hormones routinely given to cattle might affect the sons' fertility.
But there are other possibilities.
SWAN: There are persistent chemicals that are stored in the fat which are also hormonally active. Who knows? Maybe something else we don't know.
The Center for Science in the Public Interest says retrospective studies have limitations — people forget what they ate 20 years ago.
And the National Cattlemen's Beef Association points out that beef's a great source of vital iron in pregnancy.
[ COMMERCIAL: Beef, it's what's for dinner. ]
Or maybe not.
In Boston, I'm Helen Palmer for Marketplace.