Boys who are exposed to high doses of chemicals used in plastics in the womb are less likely to play with 'male' toys such as cars, finds a new study.
The University of Rochester Medical Center-led study of 145 preschool children showed, for the first time, that when the concentrations of two common phthalates in mothers' prenatal urine are elevated their sons are less likely to play with male-typical toys and games, such as trucks and play fighting.
Lead author Shanna H. Swan, professor of Obstetrics and Gynecology, director of the URMC Center for Reproductive Epidemiology, said that because testosterone produces the masculine brain, researchers are concerned that fetal exposure to anti-androgens such as phthalates - which are pervasive in the environment - has the potential to alter masculine brain development.
Phthalates are chemicals used to soften plastics. Recent studies have shown that the major source of human exposure to the two phthalates of most concern (DEHP and DBP) is through food.
These phthalates are used primarily in polyvinyl chloride (PVC), so any steps in the processing, packaging, storage, or heating of food that use PVC-containing products can introduce them into the food chain.
Phthalates are also found in vinyl and plastic tubing, household products, and many personal care products such as soaps and lotions.
Phthalates are becoming more controversial as scientific research increasingly associates them with genital defects, metabolic abnormalities, and reduced testosterone in babies and adults.
A federal law passed in 2008 banned six phthalates from use in toys such as teethers, play bath items, soft books, dolls and plastic figures.
In the study, higher concentrations of metabolites of two phthalates, di(2-ethylhexyl) phthalate (DEHP), and dibutyl phthalate (DBP), were associated with less male-typical behavior in boys on a standard play questionnaire.
No other phthalate metabolites measured in-utero was linked to the less-masculine behavior. Girls' play behavior was not associated with phthalate levels in their mothers, the study concluded.
The study is published in the International Journal of Andrology.