A new large-scale study has delivered significant insights into autism in early childhood. The research analyzed behavior and developmental traits in over 2,600 children, aiming to determine if boys and girls show different symptoms of autism between ages 1 and 4. The findings showed no significant differences in the presentation of autism symptoms between the sexes, challenging long-standing assumptions and helping refine early diagnostic tools.
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No sex-based differences found
The study, published on 26 May in Nature Human Behaviour, was conducted by scientists from the University of California w San Diego, led by neuroscientist Karen Pierce. Researchers assessed 2,618 children diagnosed with autism at an average age of 27 months. These toddlers were tested using 18 different measures, including:
- Eye-tracking attention tests
- Basic language and communication skills
- Ability to dress and feed independently
- General social and cognitive development
Results showed that boys and girls with autism scored almost identically across nearly all the assessments. According to Pierce, “We were actually incredibly surprised to find that there were no differences, no matter where, no matter how we looked.”
One minor difference
The only area where researchers found a statistically minor difference was in daily living skills, such as feeding themselves or getting dressed. On this parent-reported scale, girls slightly outperformed boys, though the difference was not deemed clinically significant.
Interestingly, among children who were not diagnosed with autism, girls scored higher than boys in expected social and developmental areas. This contrast did not extend to the autistic group, where girls and boys displayed no discernible difference in symptom expression.
Helen Tager-Flusberg, a developmental scientist at Uniwersytet Bostoński, highlighted the significance of the large sample size. She emphasized that the study's strength lies in its scale, addressing limitations of previous research that often relied on fewer than 100 participants.
Limitations of earlier studies
Prior investigations into gender differences in autism symptoms have yielded inconsistent results. Some reported behavioral distinctions, while others found none. One key issue has been that many earlier studies focused on older children, whose social experiences may influence how autism manifests. Life circumstances and external expectations can shape a child’s behavior, making it difficult to isolate innate differences tied to autism itself.
Moreover, earlier studies often involved small samples, limiting statistical reliability. By including a much larger group of children in early developmental stages, the new study avoids many of those biases, offering a clearer picture of autism in toddlerhood.
Future questions
Though the results are robust, both Pierce and Tager-Flusberg note that screening tools used to identify autism may not detect milder symptoms in girls, possibly leading to underrepresentation. Tager-Flusberg pointed out that “girls with milder symptoms may not have been identified on the screener,” which could explain the uniformity in results.
Pierce acknowledged this possibility but added that the screening identified girls at rates consistent with national data from the United States. Still, the absence of detected differences at this age raises important questions about later gender-based symptom divergence, seen in other studies involving older children.
Future follow-ups will track this same group of children over time. Researchers hope to determine if and when differences emerge and whether they stem from biological factors, social environments, or both.
This new evidence strengthens the case for early and uniform autism screening in both boys and girls, especially given the traditionally lower diagnostic rates in girls. If these results hold in further research, it may reshape how clinicians approach early childhood assessment and raise critical questions about the nature and visibility of autism across genders.
Quelle: Science News