Autism Diagnoses Rising in Females, Narrowing Gender Gap

Large population study shows females are diagnosed later than males, but rates become nearly equal by adulthood.

Published on Feb. 9, 2026

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A large population-based study in Sweden found that while boys were initially about four times more likely to be diagnosed with autism spectrum disorder (ASD) than girls, that gap began to close around age 10 and continued to shrink as diagnosis among girls increased during adolescence. By age 20, the ASD prevalence was approximately 1:1 between males and females.

Why it matters

The findings challenge the widely held assumption that autism is a male-dominated disorder, suggesting diagnostic patterns rather than true differences in prevalence may be the reason for the historical gender gap. The delayed diagnosis in females could lead to missed opportunities for early intervention and support.

The details

The study, published in The BMJ, analyzed data from the Swedish medical birth register on 2.7 million children born from 1985 to 2020. It found that overall, 2.8% of the study population were diagnosed with ASD at a median age of 14.3 years. Incidence increased for each 5-year age interval throughout childhood, reaching the highest rates between 2020 and 2022 at ages 10-14 years for males and 15-19 years for females.

  • The study included children born in Sweden from 1985 to 2020.
  • The data was collected through December 2022, with a median age of 20.1 years at the end of follow-up.

The players

Caroline Fyfe

PhD, Karolinska Institutet in Solana, Sweden, and lead author of the study.

James C. McPartland

PhD, Harris Professor of Child Psychiatry and Psychology at the Yale Child Study Center, Yale University, who commented on the study.

Diana Schendel

PhD, professor at the A.J. Drexel Autism Institute, Drexel University, who also commented on the study.

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What they’re saying

“The male-to-female ratio for autism spectrum disorder has decreased over time and with age at diagnosis, demonstrating a pattern of female catch-up. These observations highlight the need to investigate why female individuals receive diagnoses later than male individuals.”

— Caroline Fyfe, PhD, Karolinska Institutet (The BMJ)

“As awareness of autism increases or stigma associated with the diagnosis decreases, it might be these people are coming forward to get diagnoses more so later in life. Another possibility would be that, if bias and ascertainment is a factor, diagnosticians are getting better at picking up the signs of autism in girls and women.”

— James C. McPartland, PhD, Yale Child Study Center (Medscape Medical News)

“When talking with patients about their health, clinicians 'should be sensitive to [whether] they're seeing the potential for autistic behaviors in that patient that may not have been detected at a younger age.' Maybe those problems are helping to explain the health conditions that they're coming to them for.”

— Diana Schendel, PhD, A.J. Drexel Autism Institute (Medscape Medical News)

What’s next

Researchers suggest further investigating the reasons behind the delayed diagnoses in females, such as potential biases in diagnostic criteria or clinicians' ability to recognize autism symptoms in girls and women.

The takeaway

This study challenges the long-held assumption that autism is a male-dominated disorder, showing that the gender gap in diagnoses narrows significantly by adulthood. The findings highlight the need to improve early detection and diagnosis of autism in females to ensure they receive appropriate interventions and support.