Mothers' exposure to common chemicals may affect boys
Tuesday, November 24, 2009
Elevated levels of two plastic-softening chemicals in pregnant women's urine are linked to less-masculine play behavior by their sons several years later, according to a study published last week in the International Journal of Andrology.
Phthalates (THAL-ates), which are used in everything from vinyl floors to plastic tubing and soaps and lotions, are pervasive in the environment and have increasingly become associated with changes in development of the male brain as well as with genital defects, metabolic abnormalities and reduced testosterone in babies and adults.
A team of U.S. and British researchers posed a standard play questionnaire to the parents of 145 preschool-age children. Then they ranked the types of play on a scale from most masculine (such as play fighting or using trucks) to most feminine. An effect was identified among the sons of women with higher concentrations of di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) in their prenatal urine: On average, those boys scored 8 percent further away from the masculine end of the scale than other boys.
The presence of these chemicals, which are in polyvinyl chloride (PVC) tubing and often make it into the human body through consumption of processed food, was not associated with any differences in girls' play behavior.
"This is enough information to ask manufacturers to let people know when they're exposed, so they can make choices," said the study's lead author, Shanna Swan, a professor of obstetrics and gynecology at the University of Rochester Medical Center. "I don't think it's enough to ban these things." She said the study needs to be replicated at a larger scale in a different population.
Elizabeth Grossman, author of the new book "Chasing Molecules: Poisonous Products, Human Health, and the Promise of Green Chemistry," said when it comes to public disclosure, "we're not there yet" in terms of phthalates.
"The information that's out there and available on PVC products is very confusing and incomplete," Grossman said. For example, she said, she had found a yoga mat advertised as being made of "phthalate-free" PVC -- a contradiction in terms.