Lead author Shanna H. Swan, a professor at the University of Rochester's Medical Center for Reproductive Epidemiology, said because testosterone produces the masculine brain, researchers are concerned that fetal exposure to phthalates -- pervasive in the environment -- has the potential to alter masculine brain development.
A study of 145 preschool children reports found when concentrations of two common phthalates in mothers' prenatal urine were elevated their sons were less likely to play with male-typical toys and games, such as trucks and play fighting.
"Our results need to be confirmed, but are intriguing on several fronts," Swan said in a statement. "Not only are they consistent with our prior findings that link phthalates to altered male genital development, but they also are compatible with current knowledge about how hormones mold sex differences in the brain and thus behavior. We have more work to do, but the implications are potentially profound."
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; however, recent research found the major source of human exposure of phthalates is via food and food packaging.
The findings were published in the International Journal of Andrology.
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