Prenatal BPA exposure may contribute to the male bias of autism spectrum disorder. Autism has a higher prevalence in males than females. Bisphenol A (BPA) is a common chemical found in plastics, our food, and even the human placenta. Higher prenatal exposure to BPA is thought to increase the risk of autism. Researchers have identified autism candidate genes that may be responsible for the sex-specific effects of BPA. Source 5x.