In the 1990s, as growing numbers of children sought care related to their gender identity, clinicians and researchers began to notice a trend: An unexpected number of these children were autistic or had autism traits. The observation has spurred researchers to work to quantify the association.
The field is beginning to get a clear picture of the extent to which the two spectrums overlap: Gender identity and sexuality are more varied among autistic people than in the general population, and autism is more common among people who do not identify as their assigned sex than it is in the population at large — three to six times as common, according to an August study. Researchers are also making gains on how best to support autistic people who identify outside conventional genders.
Why is the prevalence of gender diversity higher in autistic people than in the general population? Social experiences are likely a main component, experts say. Compared with neurotypical people, autistic people may be less influenced by social norms and so may present their internal selves more authentically.
Biological factors may also play a role. Exposure levels to hormones such as testosterone in the womb may be linked to autism, some research shows; increased prenatal testosterone may also lead to more typically ‘male’ behaviors and to less common sexualities and gender identities, although there is some evidence against that link.