Context Autism is considered the most heritable of neurodevelopmental disorders, mainly
because of the large difference in concordance rates between monozygotic and dizygotic
twins. Objective To provide rigorous quantitative estimates of genetic heritability of autism
and the effects of shared environment. Design, Setting, and Participants Twin pairs with at
least 1 twin with an autism spectrum disorder (ASD) born between 1987 and 2004 were
identified through the California Department of Developmental Services. Main Outcome�…