Data from Swedish national and regional registries revealed that 19.8% of 3,958 children with autism spectrum disorders were exposed to prenatal smoking compared with 18.4% in the control group of 38,983 children. The study, which will appear in the Journal of Autism and Developmental Disorders, "crosses off another suspect on the list of possible environmental risk factors for ASD," lead researcher Dr. Brian Lee said.  Click here to read more.