A recent study conducted by researchers at UC San Diego School of Medicine has revealed that there are no significant clinical differences in core autism traits between male and female toddlers aged 12 to 48 months at the time of their first diagnosis. This finding challenges the longstanding belief that autism manifests differently across sexes in early childhood.

The study, published in Nature Human Behavior on May 26, 2025, assessed over 2,500 toddlers — 1,500 diagnosed with autism, 600 typically developing, and 475 developmentally delayed. Researchers evaluated 19 measures, including language development, social and motor skills, repetitive behaviors, and cognitive abilities. All assessments were conducted at the UC San Diego Autism Center of Excellence by licensed clinical psychologists.

The results indicated no significant differences between male and female autistic toddlers across these measures, except for a slight advantage in daily living skills reported by parents for females. Furthermore, when categorizing children into low, medium, and high-ability subtypes, no major clinical differences were observed between sexes within these groups.

Senior author Karen Pierce, Ph.D., emphasized the importance of these findings, noting that previous studies with smaller sample sizes had suggested sex-based differences. “There is no consensus in the field about whether females are more or less impacted than males, and that is probably because there haven’t been really large-scale studies at the earliest ages,” Pierce stated.

This comprehensive study underscores the necessity of early and unbiased diagnostic practices, ensuring that both boys and girls receive timely and appropriate interventions.

Source: UC San Diego Today