From the sciencenews.org:
Exposures in the womb to a ubiquitous family of industrial chemicals can subtly perturb preferences of boys for certain types of child’s play thought to be hardwired in the brain, a new study suggests. Phthalates are widely used solvents and plastics softeners. In this study, the greater a boy’s fetal exposure to certain phthalates, the less often he tended to engage in typically masculine play.
Read the rest of the article here.