title: Sex differences in autism spectrum disorder: evidence from a large sample of children and adolescents.
abstract: Sex differences have been found amongst toddlers and young children with autism spectrum disorder (ASD). We investigated the presence and stability of these ASD sex differences throughout childhood and adolescence. Participants (N = 325, 52 females; aged 3-18 years) consecutively received an ASD diagnosis at a clinic for assessing high-functioning ASD (mean verbal IQ = 92.6). There were no IQ sex differences. By parent report and direct observation, females had less repetitive stereotyped behaviour (RSB), with male-equivalent levels of social and communication impairment. Teachers reported males with ASD as having greater externalising and social problems than females. The female phenotype we describe was stable across our sample's age range. Their milder RSBs and less severe difficulties at school may lead to under-recognition of ASD in females.
authors.affiliation: Research Department of Clinical, Educational and Health Psychology, University College London, Gower Street, London WC1N 6BT, UK. w.mandy@ucl.ac.uk
authors.forename: William
authors.initials: W
authors.lastname: Mandy
authors.forename: Rebecca
authors.initials: R
authors.lastname: Chilvers
authors.forename: Uttom
authors.initials: U
authors.lastname: Chowdhury
authors.forename: Gemma
authors.initials: G
authors.lastname: Salter
authors.forename: Anna
authors.initials: A
authors.lastname: Seigal
authors.forename: David
authors.initials: D
authors.lastname: Skuse
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000175:diagnosis / Q000453:epidemiology*; D002675:Child, Preschool; D003147:Communication Disorders / Q000175:diagnosis / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D006306:Health Surveys; D006801:Humans; D007360:Intelligence; D007389:Internal-External Control; D008297:Male; D010641:Phenotype; D012737:Sex Factors; D012920:Social Behavior Disorders / Q000175:diagnosis / Q000453:epidemiology; D013239:Stereotyped Behavior; D006113:United Kingdom