The prenatal sex steroid theory of autism after 25 years.

This review looks at 25 years of research on whether hormones during pregnancy might contribute to autism. Studies suggest that higher levels of testosterone before birth are linked to traits often seen in autism, like slower social development and stronger focus on details. Recent research shows both male and female hormones may play a role. New scientific methods continue to support this theory and suggest new ways to study how autism develops.

This comprehensive review examines 25 years of research on the prenatal sex steroid theory of autism, originally proposed to explain the male predominance in autism diagnoses and associated cognitive patterns. The review synthesizes evidence showing that higher prenatal testosterone levels correlate with delayed social and language development, increased attention to detail, and more autistic traits. Recent research has expanded understanding to include both androgens and oestrogens in autism development. New methodological approaches using genetics and stem-cell-derived neural organoids have provided additional support for hormonal influences on neurodevelopment and identified atypical patterns in autism, opening new research directions.

Understanding prenatal hormonal influences may inform early identification strategies and personalized intervention approaches. However, this research is primarily explanatory rather than immediately actionable for clinical practice. The findings support continued research into biological mechanisms underlying autism development.

As a review article, findings depend on the quality of included studies. The abstract does not specify methodological details, sample sizes of reviewed studies, or potential publication bias considerations that may affect conclusions.

We first proposed the prenatal sex steroid theory of autism 25 years ago to account for a number of then-unexplained observations around autism, including (1) the more frequent diagnosis of autism in male than in female individuals and (2) apparent 'male-type' shifts in cognitive traits associated with autism, such as empathizing and systemizing. Here we review 25 years of research testing this theory. Early studies found that higher prenatal testosterone levels were associated with slower social, language and empathy development, greater attention to detail, stronger systemizing and more autistic traits. Subsequent studies suggested that both prenatal androgens and oestrogens are associated with autism.

New methods in genetics and using stem-cell-derived neural organoids have further indicated the importance of sex steroid hormones for neurodevelopment, as well as atypical patterns in autism. These new findings support and open new lines of research into the prenatal sex steroid theory of autism.