Autism Spectrum Disorders (ASD) are behaviorally defined neurodevelopmental disorders. The best known yet less understood characteristic of autism is its unexplained male preponderance. Using a biosocial perspective, the goal of this article is to draw attention to the role of gender-based socialization practices and behavioral expectations during the clinical evaluation. Together with gender-biased standardized instruments used to support the diagnosis of ASD, these factors may contribute to the higher prevalence of males with ASD. The assumption is that both biological sex and gender identity contribute, in distinct ways, to the male preponderance. While sex is genetically defined, gender is a psycho-social construct expressed through specific behaviors consistent with socio-cultural expectations based on individuals' genetic sex. As such, clinicians are influenced by the expected behaviors based on the prominent gender socialization attribute. Concurrently, most standardized clinical instruments used for the diagnosis of ASD do not include gendered-norms. The first question raised here pertains to the role of a child's biological sex and the effect of hormones, be it protective versus increase vulnerability for ASD. The second question focuses on the function of gendered socialization practices, especially in regard to externalizing and internalizing behaviors and how these practices may bias the diagnosis and thus the sex ratio.