Study Finds No Sex Differences in Autism Traits During Initial Diagnosis in Toddlers

Research conducted by the University of California - San Diego reveals that at the time of their first autism diagnosis, toddlers—regardless of sex—exhibit similar behavioral and developmental characteristics. Despite males being over four times more likely to receive an autism diagnosis than females, the study shows no meaningful clinical differences between boys and girls in early autism traits. The large-scale study, published in Nature Human Behaviour, assessed over 2,500 toddlers aged 12 to 48 months, including those diagnosed with autism, typically developing children, and those with other developmental delays.

Assessments measured various aspects such as language, social skills, motor skills, repetitive behaviors, and cognitive abilities, with evaluations conducted by licensed clinical psychologists. The findings indicated that most autism-related measures were consistent across sexes, with only a slight difference observed in daily living skills, where females scored marginally higher. When categorizing children into subtypes based on ability levels, no major sex-based differences surfaced within these groups or over time.

Interestingly, the study confirmed that typically developing females generally outperform males on social skills and language tests, aligning with existing literature on typical development. However, these differences did not appear within autistic children at early ages. The results suggest that earlier research indicating sex differences may be influenced by smaller sample sizes or methodological limitations.

Lead researcher Dr. Karen Pierce emphasized that the absence of early sex differences in autism traits could imply that such disparities develop later due to socialization or biological factors, rather than being inherent from the onset. The study highlights the importance of focusing on clinical subtypes over sex when developing tailored interventions, with early support potentially improving outcomes for all children.

Overall, this comprehensive research contributes valuable insights into early autism development and encourages further longitudinal studies to track potential sex-based divergence over time.