--- - |2 Unusual social behaviors have been central to our notions of autism spectrum disorders since their original descriptions. We have come to recognize that such behaviors are broadly distributed beyond the classic phenotype and may be induced by postnatal experiences involving insufficient care. Sex differences have also been noted, and a paper in the current issue by Mandy and colleagues, demonstrates different longitudinal trajectories in boys and girls in autistic social traits from middle childhood to mid‐adolescence. These and related findings are evidence of both progress in our understanding and how much we still need to learn to understand the social behaviors associated with autism spectrum disorders. - Journal of Child Psychology and Psychiatry, Volume 59, Issue 11, Page 1125-1126, November 2018.