Does the Extreme Male Brain Hypothesis of Autism Apply More to Females Than Males? A Systematic and Meta-Analytic Approach.

The authors did not formally assess risk of bias in the included studies. The findings come from self-report questionnaires, not clinical examination or therapy outcomes. Different questionnaire versions were rescaled to percent of maximum score, so raw score differences may not be directly comparable. Age was not included in models because it was inconsistently reported. Much of the large sample came from a small number of research groups, which may limit generalisability. The analysis tests a theoretical framework using group averages; it does not diagnose individuals or show that any treatment works.

Funding: Canada Research Chair to BJC. Authors declared no conflicts of interest.

Do not conclude that these questionnaires can identify autism in an individual patient or that autistic females are more male-typical in a clinical sense. The study compares group averages from self-report empathy and systemizing scores and does not test diagnosis, prognosis or treatment.