Examining Diagnostic Trends and Gender Differences in the ADOS-II.
ADOS-II gives girls lower severity scores, so use extra data before you clear them from the autism spectrum.
01Research in Context
What this study did
The team pulled 6,183 existing ADOS-II records. They asked a simple question: do boys and girls get the same severity scores?
They looked at total algorithm scores, plus the two main parts—restricted/repetitive behaviors and social-communication.
What they found
Boys scored higher on every severity composite. Girls landed lower even when clinicians later felt autism was likely.
The gap stayed after age, IQ, and language level were taken out.
How this fits with other research
Duvekot et al. (2017) saw the same pattern years earlier. Girls needed bigger emotional problems and fewer repetitive moves to earn a diagnosis. The new data show the ADOS-II itself hands girls lower numbers, so the tool is part of the problem.
Hus et al. (2013) warned that child traits like poor language can pump up ADI-R severity. The 2025 paper adds gender as another built-in pump: boys look worse on the ADOS-II even when girls have the same core autism.
Pilowsky et al. (1998) found no gender gap between ADI-R and CARS. That looks like a clash, but they studied different tools and far smaller samples. The ADOS-II, not the older interviews, is where the male score bump lives.
Why it matters
If you run ADOS-II modules and stop at the cut-off, girls can slip past. Watch for quiet but clear social struggle, camouflaging, or advanced play that hides rigidity. When scores sit just below the line, gather extra parent report, sensory data, or classroom clips before you rule autism out.
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02At a glance
03Original abstract
Approximately 3-4 boys for every girl meet the clinical criteria for autism in studies of community diagnostic patterns and studies of autism using samples of convenience. However, girls with autism have been hypothesized to be underdiagnosed, possibly because they may present with differing symptom profiles as compared to boys. This secondary data analysis used the National Database of Autism Research (NDAR) to examine how gender and symptom profiles are associated with one another in a gold standard assessment of autism symptoms, the Autism Diagnostic Observation Schedule II (ADOS-II; Lord, C., Luyster, R., Guthrie, W., & Pickles A. (2012a). Patterns of developmental trajectories in toddlers with autism spectrum disorder. Journal of Consulting and Clinical Psychology, 80(3):477-489. https://doi.org/10.1037/a0027214 . Epub 2012 Apr 16. PMID: 22506796, PMCID: PMC3365612). ADOS-II scores from 6183 children ages 6-14 years from 78 different studies in the NDAR indicated that gender was a significant predictor of total algorithm, restrictive and repetitive behavioral, and social communicative difficulties composite severity scores. These findings suggest that gender differences in ADOS scores are common in many samples and may reflect on current diagnostic practices.
Journal of autism and developmental disorders, 2025 · doi:10.1007/BF01046216