Sex Bias in Autism: Emerging Research and Implications

Autism spectrum disorder (ASD) has historically been diagnosed more frequently in males. Yet, growing evidence suggests this disparity isn’t necessarily due to a true difference in prevalence, but rather a significant sex bias in identification and diagnosis. Recent research is shedding light on the biological and environmental factors contributing to this bias, and highlighting the need for improved screening methods, particularly for females.

Understanding the Diagnostic Bias

For years, the diagnostic criteria for autism were developed based on observations primarily of males. This has led to a situation where autistic traits that manifest differently in females – often presenting as more subtle or masked – are frequently overlooked. Females may be more likely to internalize their difficulties, leading to presentations that are misdiagnosed as anxiety or depression.

New Insights from Recent Studies

Several recent studies, as of February 2026, are contributing to a more nuanced understanding of sex-related differences in autism:

• Genetic Variations: Research indicates that the occurrence of de novo genetic variations (new mutations) in autism differs between sexes. Preprints highlight the influence of sex on these variations, suggesting a biological basis for differing presentations.
• Neural Connectivity: Studies are as well exploring how neural pathways differ in their altered connectivity patterns in autism, with variations observed between males and females.
• Prenatal COVID-19 Exposure: A recent study found a link between prenatal exposure to COVID-19 infection and an increased likelihood of autism in baby girls. This suggests a potential environmental factor that may disproportionately affect females.
• Brain Morphology: Research is examining sex-specific alterations in brain structure and network connections in adolescents with autism.

The Impact of Autistic Traits and Gender During Stressful Times

The COVID-19 pandemic provided a unique opportunity to study the interplay between autistic traits, gender, and emotional responses to stress. Research has shown that individuals with higher autistic traits and females experienced stronger feelings of anger and fear during the pandemic compared to those with lower traits and males. This suggests a heightened emotional susceptibility to pathogen-related stressors in these groups.

PTSD and Autism: A Sex-Specific Risk

Individuals with high autistic traits are at a higher risk of developing post-traumatic stress disorder (PTSD) following traumatic events. Studies indicate this risk is particularly pronounced in women with high autistic traits, potentially due to a mediating role of anxiety sensitivity. This highlights the need for targeted mental health support for this vulnerable population.

The Need for Improved Screening and Diagnosis

Experts emphasize the need for better tools and training to mitigate sex bias in autism identification. Simply increasing clinician training with current, potentially biased measures may not be sufficient. Developing and implementing more effective screening and diagnostic approaches that account for the diverse ways autism presents in females is crucial.

Key Takeaways

• Sex bias significantly impacts autism diagnosis, leading to underdiagnosis in females.
• Recent research is uncovering biological and environmental factors contributing to these sex-related differences.
• The COVID-19 pandemic highlighted the increased emotional vulnerability of individuals with autistic traits, particularly females.
• Improved screening tools and clinician training are essential to address the diagnostic bias and ensure equitable access to support for all individuals with autism.