Neuroimaging insights into transgender and gender nonconfirming youth: a scoping review

Gender incongruence in adolescents is a relevant condition in which the gender identity of a person does not correspond with the birth-assigned sex. Individuals with gender dysphoria can experience a distressing burden. The etiology seems to be predominantly biological, but only a few neurobiological correlates have been identified and are not yet embedded in a broader context. The aim of this review is to present an overview about the current state of the literature regarding MRI brain findings in adolescents < 22 years of age with GD/GI also including non-binary identifying adolescents < 22 years. Findings will be discussed considering (a) sample characteristics, (b) the status of possible hormonal therapy including puberty blockers and (c) non-binary identifying persons and from a general ethical perspective.

A systematic review was conducted using PubMed/Medline with keywords: "gender dysphoria," "gender incongruence," "gender identity," "non-binary," "MRI," and "adolescents." The term "transsexualism" was used to include literature published before the term change related to ICD-11. The protocol was pre-registered (INPLASY2023110074).

We scanned 360 articles and finally included n = 20 studies in the review. We found that studies on adolescents with gender dysphoria are mostly addressing functional imaging. Studies were predominantly limited by cross-sectional designs. N = 3 longitudinal studies were performed in female-to-male-transgender persons before and after beginning with gender affirming hormonal therapy (GAHT). To our knowledge there has never been performed a longitudinal study in male to female adolescents during GAHT. Non-binary aspects were mostly not taken into account. Ethical implications concerning the interpretation of neuroimaging findings in this field have been rarely discussed.

There is a lack of robust neuroimaging data on GI/GD adolescents, particularly from longitudinal studies, which are crucial for understanding neurobiological processes. Non-binary identifying adolescents should be given more consideration in research. Future research should include non-binary adolescents and integrate ethical considerations to prevent misinterpretation or stigmatization. Neuroimaging should not reduce gender diversity to neurobiology but rather contribute to a more nuanced understanding of gender identity.