The male to female ratio is raised in autism spectrum disorders (ASD). Previous studies have suggested that girls with ASD have more problems with communication than boys, but boys show more repetitive behaviours than girls. In this study, 20 girls, 1.8-3.9 years of age were matched for chronological and developmental age with 20 boys with suspected ASD. All the children were recruited after population screening and referral by Child Health Care Services to a specialised neuropsychiatry clinic, where they underwent comprehensive neuropsychiatric assessments. Comparisons were made with regard to diagnosis, developmental profiles and global disability. No significant gender differences were found. There were strong correlations between results obtained in different developmental areas. The results suggest that either (1) previous studies finding clear gender differences may have overrated discrepancies between girls and boys in ASD, or that (2) there may be girls, who will not be identified in the early years with our current screening instruments. More research with a much larger population representative study samples is required. (Contains 5 tables.)