Fig. 1
From: The role of sex-differential biology in risk for autism spectrum disorder
Approaches used to estimate ASD prevalence and male:female ratio. Different approaches may identify different overall, and sex-specific, prevalence rates. a Screening populations in full, irrespective of existing diagnostic status. b Analysis of records in existing, standardized registries. c Collating and/or sampling and interpreting available records from scholastic or medical records. d Baby siblings studies, where researchers prospectively monitor the younger siblings of autistic children for recurrence of ASD and other traits of interest. Filled figures represent individuals with ASD