Study Reveals No Gender Disparities in Autism Diagnosis Among Toddlers

A recent study conducted by researchers at the University of California, San Diego, has revealed that there are no significant clinical differences in autistic traits between male and female toddlers at the time of their initial autism diagnosis. This finding challenges the prevailing notion that males are more affected by autism compared to females, as they are more than four times more likely to receive a diagnosis.

Published in the journal Nature Human Behavior, the study assessed over 2,500 toddlers aged between 12 and 48 months from 2002 to 2022. Among these, 1,500 were diagnosed with autism, while the remaining participants were categorized as typically developing or developmentally delayed. The assessment process involved evaluating various aspects, including language development, social and motor skills, core autism traits such as repetitive behaviors, cognitive abilities, and other developmental indicators. Eye-tracking technology was also utilized to examine social attention.

The researchers found that:

• No substantial clinical differences were observed between male and female autistic toddlers across nearly all metrics, with the exception of a slight advantage for females in daily living skills based on parental reports.
• When categorized into low, medium, and high-ability subtypes of autism, no major clinical distinctions were found between genders within these groups.
• Over the developmental trajectory from 12 to 48 months, the researchers noted no significant differences in clinical outcomes between the sexes in autistic toddlers.
• Minimal gender disparities were also identified among developmentally delayed toddlers.

Previous research with smaller sample sizes had suggested potential differences between genders in autistic traits among toddlers. However, this latest study stands out as one of the largest and most comprehensive analyses to date, particularly focusing on very young children. Senior researcher Karen Pierce, Ph.D., who heads the Autism Center of Excellence at UC San Diego, emphasized the necessity for large-scale studies at early developmental stages to clarify these findings.

Despite the lack of gender differences in autistic traits, the study did reveal that typically developing female toddlers outperformed their male counterparts in more than half of the assessed areas, particularly in social skills, language development, and daily living skills. This observation aligns with previous literature indicating that female toddlers often exhibit accelerated development compared to males.

The implications of these findings are significant for understanding autism's development, enhancing early detection, and improving intervention strategies. The study suggests that focusing on the clustering of autistic traits into scientifically valid subtypes could provide more effective insights into clinical heterogeneity and tailored interventions.

Researcher Pierce noted that enhancing communication and language abilities in toddlers with autism from an early age could significantly improve their ability to meet their needs and contribute positively to society. The aim is to support every child in reaching their full potential.

For further information regarding this study, refer to the original publication: Sanaz Nazari et al, 'Large-scale examination of early-age sex differences in neurotypical toddlers and those with autism spectrum disorder or other developmental conditions,' Nature Human Behaviour (2025). DOI: 10.1038/s41562-025-02132-6.