Structural, functional and metabolic brain differences between groups with opposite gender identity and sexual orientation. A systematic review on the neuroimaging literature up to 2018

Human sexuality is a complex reality, characterised by gender identity and sexual orientation. A widespread approach to study human sexuality is to compare groups with opposite sexual gender identity and sexual orientation such as cisgenders vs transgenders and heterosexuals vs homosexuals. Cisgenderism refers to individuals whose sense of gender identity corresponds to their natal sex, while transgenderism is characterized by an incongruity between biological sex and psychological gender with cross-gender identification. Heterosexuality refers to those who feel an emotional, romantic or sexual attraction towards the opposite sex, while homosexuality is characterized by an emotional, romantic or sexual attraction towards same sex individuals.
Neuroimaging studies have found brain differences between these groups of individuals. Nevertheless, their results are conflicting, and limitations such as small samples’ sizes and the considerable overlap between such groups, makes it difficult to draw accurate conclusions.
This systematic review and meta-analysis explored structural, functional and metabolic features of the ‘cisgender brain’ compared with the ‘transgender brain’ before hormonal treatment and the ‘heterosexual brain’ compared to the ‘homosexual brain’ from the analysis of the neuroimaging literature. Processing the information that conform this dataset suggests that neuroanatomy, neurophysiology and neurometabolism in transgenders resemble those of their natal sex rather than those of their experienced gender and in homosexuals these resemble those of their same sex heterosexual population rather than their opposite sex heterosexual population. However, the small number of studies that contributed data, their small sample size, the incompleteness of the data, and the heterogeneity of the investigations that were included in this systematic review do not allow drawing general conclusions.
This dataset contains all data extracted from the publications included, as well as the search strategy and the results of processing the information extracted from the articles.

Frigerio, Alberto; Ballerini, Lucia; Valdés Hernández, Maria del C. (2018). Structural, functional and metabolic brain differences between groups with opposite gender identity and sexual orientation. A systematic review on the neuroimaging literature up to 2018, 2004-2018 [dataset]. University of Edinburgh. College of Medicine and Veterinary Medicine. School of Clinical Sciences. Centre for Clinical Brain Sciences. http://dx.doi.org/10.7488/ds/2412.