Autism Heritability Stable Over Time

A large twin analysis of Swedish cohorts spanning births from 1982–2008 finds consistently high heritability for autism spectrum disorder and autistic traits across cohorts. The pattern implies that the surge in diagnosed cases over recent decades is unlikely to be explained by new, large environmental risk factors. — If genetic contribution to autism is stable, policy and public discussion should focus more on diagnostic practices, service capacity, and social determinants rather than assuming new environmental epidemics.