Understanding Sex and Gender Effects on Autism Spectrum Disorder and Obsessive-Compulsive Disorder: Clinical Presentation and Risk Factors.

Autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD) exhibit significant sex and gender differences in prevalence, clinical presentation, and risk factors. Males are diagnosed with ASD 4 times more frequently than females, and females show slightly higher OCD prevalence, though diagnostic biases may obscure true rates. Current diagnostic criteria predominantly reflect male phenotypes, contributing to underdiagnosis or delayed diagnosis in females who often camouflage symptoms and present with less stereotypical behaviors. Here, we examine sex and gender influences on these disorders across clinical presentation, genetic factors, and developmental risks. Beyond sex, we emphasize the understudied role of gender, including elevated prevalence in gender-diverse populations and the influence of gender norms on symptom expression. We examine how other sociodemographic factors, such as race, ethnicity, and socioeconomic status, can compound diagnostic disparities. Finally, we provide recommendations for reforming diagnostic criteria and clinical practice to better serve females, gender-diverse individuals, and marginalized populations. Overall, implementing sex- and gender-informed diagnostic practices is essential to reduce diagnostic delays, improve treatment outcomes, and ensure equitable care for all individuals affected by ASD and OCD.