Male-to-Female Ratio for Autism Has Decreased Over Time

FRIDAY, Feb. 6, 2026 (HealthDay News) -- There has been a decrease in the male-to-female ratio for autism spectrum disorder (ASD) over time and with increasing age at diagnosis, according to a study published online Feb. 4 in The BMJ.Caroline Fyfe, Ph.D., from the Karolinska Institutet in Solna, Sweden, and colleagues conducted a population-based, prospectively collected birth cohort study involving 2,756,779 liveborn children recorded in the Swedish medical birth register between 1985 and 2020 to examine changes in the male-to-female ratio in diagnoses of ASD.The researchers found that by the end of follow-up, ASD was diagnosed in 2.8 percent of the individuals born between 1985 and 2020. With each five-year age interval throughout childhood, the incidence rate for ASD increased, peaking at 645.5 and 602.6 per 100,000 person-years for male and female individuals at age 10 to 14 years and 15 to 19 years, respectively, in 2020 to 2022, and then decreased. For each calendar period and birth cohort between 1985 and 2020, the age-specific incidence of ASD increased. With increasing age at diagnosis and by calendar period for those aged older than 10 years, there was a decrease in the male-to-female ratio. The cumulative male-to-female ratio for the incidence of ASD was 1.2 by age 20 years for the final year of follow-up in 2022. The cumulative male-to-female ratio was suggested to reach parity at age 20 years by 2024 in further projections of these trends."The decreasing male-to-female ratio over time highlights the need to investigate why female individuals receive a diagnosis of ASD later than male individuals," the authors write.Abstract/Full TextEditorial.Sign up for our weekly HealthDay newsletter

Male-to-Female Ratio for Autism Has Decreased Over Time

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