Progress in Understanding the Causes of Autism Spectrum Disorders and Autistic Traits: Twin Studies from 1977 to the Present Day
and Rosa Hoekstra2 (1) Genes Environment Lifespan (GEL) Laboratory, Department of Psychological Sciences, Centre for Brain and Cognitive Development, Birkbeck, University of London, Malet Street, London, WC1E 7HX, UK (2) Department…