Autism spectrum disorder (ASD) is widely regarded to be one of the most severe of the childhood psychiatric conditions. Until now, the root causes of this condition have been viewed in a dichotomous ‘either/or’ fashion: some researchers saying “autism is a genetic disease”, others relying purely on a panoply of environmental causes. Remarkably, the interaction between genetic and environmental factors have not been widely investigated although synergistic effects have been found for other neurodevelopmental disorders such as depression and may bring important insights into the prevention of developing autism spectrum disorder. This project will use an animal model (mice) to investigate the interaction of being genetically vulnerable to develop this disease with a known environmental predisposing condition, prenatal stress on developing autism-like phenotypes. Additionally, we will investigate whether these factors affect the sexes differentially. The latter may elucidate the male preponderance, a well known, but understudied aspect of autism spectrum disorder. Knowledge about these mechanisms may contribute to the discovery of some important aspects of the etiology of autism spectrum disorder. Furthermore, understanding the sex-specific gene-environment interaction affecting the development of autism-like behaviors may likely offer new avenues of enquiry into autism spectrum disorder and may provide unique insights into the neurobiology of the condition. Half of the control mice and half of the mice that are genetically vulnerable to develop the condition will receive prenatal stress. When the mice reach puberty they will be assayed for behaviors typical of autism spectrum disorder. Also certain areas of the mice’s brain will be assayed to determine the relationship between typical behaviors and readability of the genetic information. Studying the readability of the genetic information (epigenetics) can elucidate the underlying mechanisms of how genetic and environmental factors and their interaction effect causes typical of autism-like behaviors to arise.