Do Biological Sex and Early Developmental Milestones Predict the Age of First Concerns and Eventual Diagnosis in Autism Spectrum Disorder?

There was no neurotypical control group, so the study cannot compare these caregiver-reported milestone ages with typical development. The analyses used current IQ measured at enrollment, not IQ at the age of diagnosis. The sample was limited to children with IQ above 70 and those who completed ADOS-2 Module 3 or 4, so findings may not apply to minimally verbal or more cognitively impaired children. Females were included only if they met conventional gold-standard ASD criteria, which may have removed sex differences that do not fit the usual male-based presentation. Milestone and diagnostic ages came from retrospective caregiver reports, which can be affected by memory and by parents reporting more language delay as children age. The sample was mostly white and non-Hispanic and not powered to detect race or ethnicity differences. Families came from well-resourced research centers, and two sites had lower age of diagnosis for females than the other two sites, so population-level timing may differ. Some analyses had missing data, and 18 participants were excluded from age-at-diagnosis analyses.

The supplied text lists NIH extramural research support and describes an NIH ACE GENDAAR Network study. No author conflict-of-interest declaration is provided in the supplied text.

Do not conclude that earlier language milestones caused later diagnosis in girls. In these caregiver reports, girls spoke earlier but had later first concerns; age at diagnosis only approached significance, diagnostic lag did not differ, and the milestones themselves did not individually predict diagnosis.