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Transgender Brains

Scientific research into the brains of cisgender and transgender individuals has shown a remarkable difference between the brains of those individuals born cisgender and those who are transgender. These differences are mainly in structure and functionality that corresponds to the brain of the gender the transgender individual feels they are verses the gender they were assigned at birth.


Before Hormone Replacement Treatment

In a 2013 study done by Dr. Antonio Guillamon, Dr. Carme Junque, and Dr. Esther Gómez-Gil, they found, by using MRI images of brains of cisgender individuals and transgender individuals, that the brains of male-to-female (MTF) transgender individuals looked more like females in structure and female-to-male (FTM) transgender individuals looked more like males in structure.1) This was before they began any hormone replacement therapy (HRT).

In their study, Dr. Guillamon, found that MTF transgender individuals displayed “less gray matter volume in the left somatosensory and primary motor cortices as well as the posterior cingulate and calcarine gyri and the precuneus than male controls and FtMs. These findings suggest that homosexual MtFs have a feminine cortical pattern”.2) Likewise, MTF transgender individuals showed a smaller “left superior posterior hemisphere of the cerebellum and smaller volume than female controls in the right inferior orbitofrontal cortex”.3)

Cortical thickness of untreated homosexual male-to-female (MtF) and female-to-male (FtM) transsexuals. Upper panel: (a) comparison between male and female controls. Bottom panel: (b) comparison between MtF and male controls; c comparison between FtM and male controls. All significant comparisons showed the F > M pattern. Note that both MtFs (b) and FtMs (c) show a feminine pattern although they differ in different regions from males than do control females. L left hemisphere, R right hemisphere. Zubiaurre-Elorza, Junque, Gómez-Gil, Segovia, Carrillo & Guillamon, 2013, with permission4)

Dr. Guillamon also looked at the Cortical Thickness (CTh) of their subjects and found that MTF transgender individuals CTh was the same as cisgender females and that FTM transgender individuals CTh was the same as cisgender males.5)

After Hormone Replacement Therapy

Dr. Guillamon found that after hormone replacement therapy, any slight differences in the brain structure of transgender individuals from their preferred gender completely went away. MTF and FTM transgender brains tended to look so similar to their desired gender after HRT that they could not be distinguished.6)

In a study done by Spizzirri et al. (2018), they found that the grey matter, cerebrospinal fluid, white matter, total tissue volume, and total intracranial volume all were lower in transgender women than the cisgender males in the study 7).

In a seperate study by Zubiaurre-Elorza et al. (2021), the effects of testosterone was measured on transgender males. In MRI's of their brains after treatment with testosterone, their brain volume and structure aligned to match cisgender males 8).


In a 2015 study by Dr. Sarah M. Burke and her colleagues, they examined adolescents who reported having Gender Dysphoria (GD). Those who considered themselves MTF transgender, when exposed to Androstadienone which elicited a hypothalamic activation that matched their experienced gender verses the gender they were assigned at birth.9)

In another study conducted by Dr. Burke in 2014 found that Click-Evoked Otoacoustic Emissions in adolescents caused a response in the ear that matched that of their experienced gender verses that of their gender assigned at birth.10)


1) , 2) , 3) , 4) , 5) , 6)
Guillamon, A., Junque, C., & Gómez-Gil, E. (2016). A Review of the Status of Brain Structure Research in Transsexualism. Archives of Sexual Behavior, 45(7), 1615–1648.
Spizzirri, G., Duran, F. L. S., Chaim-Avancini, T. M., Serpa, M. H., Cavallet, M., Pereira, C. M. A., Santos, P. P., Squarzoni, P., da Costa, N. A., Busatto, G. F., & Abdo, C. H. N. (2018). Grey and white matter volumes either in treatment-naïve or hormone-treated transgender women: a voxel-based morphometry study. Scientific Reports, 8(1), 736.
Zubiaurre-Elorza, L., Cerdán, S., Uribe, C., Pérez-Laso, C., Marcos, A., Rodríguez del Cerro, M. C., Fernandez, R., Pásaro, E., & Guillamon, A. (2021). The Effects of Testosterone on the Brain of Transgender Men. Androgens: Clinical Research and Therapeutics, 2(1), 252–260.
Burke, S. M., Cohen-Kettenis, P. T., Veltman, D. J., Klink, D. T., & Bakker, J. (2014). Hypothalamic Response to the Chemo-Signal Androstadienone in Gender Dysphoric Children and Adolescents. Frontiers in Endocrinology, 5.
Burke, S. M., Menks, W. M., Cohen-Kettenis, P. T., Klink, D. T., & Bakker, J. (2014). Click-evoked otoacoustic emissions in children and adolescents with gender identity disorder. Archives of Sexual Behavior, 43(8), 1515–1523.
neuroscience/transgenderbrains.txt · Last modified: 2023/12/07 11:20 by bishop