Due Deferens

Separate studies show chemicals, cigarettes may affect male birth rate

The percentage of boys born in the U.S. and Japan each year has gradually declined over the last three decades, a new study says -- and pollutants are a possible cause. "Male reproductive health is in trouble," says lead researcher Devra Lee Davis of the University of Pittsburgh, noting that both adult fertility and fetal chances seem to be affected. The study, published in the online journal Environmental Health Perspectives, calls the trend "a serious matter" that could be caused by exposure to chemicals like dioxin and mercury; it also points to factors including stress, obesity, and fertility treatments. The true cause, says Davis, is "something we need to find out and act upon." Because a woman without a man -- well, she'd probably be fine, but still. Meanwhile, a British study says smokers are twice as likely to conceive girls, suggesting that nicotine may affect sperm. Yes, smoke gets in your Y's -- but picking up puffing in an effort to determine your child's gender is not recommended.