Abstract
This preregistered study examined whether the gender identity phenotype differs between autistic and non-autistic children and adolescents, as well as whether gender identity traits aggregate similarly within their families. Study 1 involved four matched groups of autistic and non-autistic gender diverse youth referred to a UK specialist gender clinic, as well as cisgender autistic and non-autistic youth (n = 45 per group). Participants completed measures of gender typicality, discontentedness, anticipated future identity, and (parent-reported) dysphoria. Despite large and significant differences between cisgender and gender diverse youth across all gender-related measures, there were no significant differences between autistic and non-autistic participants within either gender group. Study 2 assessed recalled childhood gender behaviors and current gender dysphoria in the caregivers of participants from each group (N = 203). Caregivers of gender-referred youth, regardless of autism status, reported higher current dysphoric traits than caregivers of cisgender youth, but no differences were observed in recalled childhood gender-related behavior. Overall, the findings indicate that the gender phenotype of autistic youth is comparable to that of non-autistic youth within the same gender identity group, challenging the assumption that gender diversity in autism arises from different underlying mechanisms. Clinically, these results support equitable access to gender-related care for autistic and non-autistic gender diverse youth.