title: Sexually dimorphic facial features vary according to level of autistic-like traits in the general population.
abstract: BACKGROUND
  In a recent study, Bejerot et al. observed that several physical features (including faces) of individuals with an autism spectrum disorder (ASD) were more androgynous than those of their typically developed counterparts, suggesting that ASD may be understood as a 'gender defiant' disorder. These findings are difficult to reconcile with the hypermasculinisation account, which proposes that ASD may be an exaggerated form of cognitive and biological masculinity. The current study extended these data by first identifying six facial features that best distinguished males and females from the general population and then examining these features in typically developing groups selected for high and low levels of autistic-like traits.
  
  
  METHODS
  In study 1, three-dimensional (3D) facial images were collected from 208 young adult males and females recruited from the general population. Twenty-three facial distances were measured from these images and a gender classification and scoring algorithm was employed to identify a set of six facial features that most effectively distinguished male from female faces. In study 2, measurements of these six features were compared for groups of young adults selected for high (n = 46) or low (n = 66) levels of autistic-like traits.
  
  
  RESULTS
  For each sex, four of the six sexually dimorphic facial distances significantly differentiated participants with high levels of autistic-like traits from those with low trait levels. All four features were less masculinised for high-trait males compared to low-trait males. Three of four features were less feminised for high-trait females compared to low-trait females. One feature was, however, not consistent with the general pattern of findings and was more feminised among females who reported more autistic-like traits. Based on the four significantly different facial distances for each sex, discriminant function analysis correctly classified 89.7% of the males and 88.9% of the females into their respective high- and low-trait groups.
  
  
  CONCLUSIONS
  The current data provide support for Bejerot et al.'s androgyny account since males and females with high levels of autistic-like traits generally showed less sex-typical facial features than individuals with low levels of autistic-like traits.
authors.affiliation: School of Computer Science and Software Engineering, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.
authors.forename: Syed Zulqarnain
authors.initials: SZ
authors.lastname: Gilani
authors.affiliation: Neurocognitive Development Unit, School of Psychology, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.|Telethon Kids Institute, University of Western Australia, 100 Roberts Road, Subiaco, 6008 Perth, WA Australia.
authors.forename: Diana Weiting
authors.initials: DW
authors.lastname: Tan
authors.affiliation: Neurocognitive Development Unit, School of Psychology, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.
authors.forename: Suzanna N
authors.initials: SN
authors.lastname: Russell-Smith
authors.affiliation: Neurocognitive Development Unit, School of Psychology, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.
authors.forename: Murray T
authors.initials: MT
authors.lastname: Maybery
authors.affiliation: School of Computer Science and Software Engineering, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.
authors.forename: Ajmal
authors.initials: A
authors.lastname: Mian
authors.affiliation: School of Anatomy, Physiology and Human Biology, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Eastwood
authors.affiliation: School of Computer Science and Software Engineering, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.
authors.forename: Faisal
authors.initials: F
authors.lastname: Shafait
authors.affiliation: School of Dentistry/Oral Health Centre of Western Australia, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.
authors.forename: Mithran
authors.initials: M
authors.lastname: Goonewardene
authors.affiliation: Neurocognitive Development Unit, School of Psychology, University of Western Australia, 35 Stirling Highway, Crawley, 6009 Perth, WA Australia.|Telethon Kids Institute, University of Western Australia, 100 Roberts Road, Subiaco, 6008 Perth, WA Australia.
authors.forename: Andrew Jo
authors.initials: AJ
authors.lastname: Whitehouse
keywords: Autism; Autism spectrum disorder; Facial features; Femininity; Gender defiant disorder; Hypermasculinisation; Masculinity; Raine study