Gray matter volume differences between transgender men and cisgender women: A voxel-based morphometry study

Area of Science:

• Neuroscience
• Neuroimaging
• Gender Studies

Background:

• Gender dysphoria (GD) involves distress from incongruence between gender identity and biological sex.
• Transgender individuals may experience altered brain volumes, but findings across studies are inconsistent.
• Previous research has primarily focused on transgender women, with less data on transgender men.

Purpose of the Study:

• To investigate neuroanatomical differences in transgender men.
• To compare gray matter volume (GMV) in transgender men and cisgender women.
• To examine brain structure in transgender men without physical interventions.

Main Methods:

• T1-weighted magnetic resonance imaging (MRI) scans were acquired.
• 21 transgender men and 21 age- and sex-matched cisgender women participated.
• Voxel-based morphometry (VBM) was used for whole-brain comparisons of GMV.

Main Results:

• Transgender men showed greater GMV in the right posterior cingulate gyrus and left occipital pole.
• Transgender men had lower GMV in the left middle temporal gyrus compared to cisgender women.
• The posterior cingulate gyrus difference remained significant after controlling for sex hormones; occipital pole and middle temporal gyrus did not.

Conclusions:

• Transgender men possess altered brain structures compared to cisgender women.
• Enlarged posterior midline structures may influence self-referential processing and visual perception in transgender individuals.
• Sex hormones, particularly testosterone, appear to influence specific brain regions investigated.