Scientists concur that a combination of genetic and environmental factors increases risk for autism. However, the way that the two interact has been understudied. This project will leverage data from a high-risk pregnancy cohort called MARBLES to examine the influence of exposure to pesticides during pregnancy on ASD symptoms, including cognitive impairment and other psychiatric challenges in those children. In addition, an exploratory study will be launched to investigate the association between pesticide exposure during pregnancy and gene expression in mother and child with autism, something that has never been done before. By using this valuable longitudinal data collected prenatally, the study will help identify preventable risk factors and contribute to understanding the role of genetics and environment in autism diagnosis.