Paul Whiteley, Lynda Todd, Kevin Carr and Paul Shattock

ESPA Research, The Robert Luff Laboratory, Unit 133i Business and Innovation Centre (BIC), Sunderland Enterprise Park, Wearfield, Sunderland SR5 2TA, UK.

Abstract

Skewed sex ratios indicative of a greater preponderance of males over females (approximating 4:1) has perhaps been the most constant collective finding in autism spectrum conditions. More recent investigations have indicated a potential change to traditional estimates of gender ratios. We undertook analysis to calculate contemporaneous gender ratios based on collective and individual sub-diagnoses. A sample of 1963 children diagnosed with autism (n = 460), Asperger syndrome (n = 366) or autism spectrum disorder (ASD) (n = 1137) were included for study. The overall gender ratio based on a year of birth between 1986–2007 was 7.38:1. Differences were found amongst the sub-diagnoses for the same period (autism = 6.54:1, Asperger syndrome = 12.07:1; ASD = 6.84:1). Analysis of annual trends indicated an irregular upwards tendency to gender ratios indicative of increasing over-representation of males with an autism spectrum condition despite no indication of greater disparity in population sex ratios at birth. Further independent studies are required to corroborate our findings.