Table 4.

Brain volume of untreated homosexual male-to-female transsexuals

Brain region/aspect	Normative sex differences (M vs. F)	Sample size and age (M ± SD)	Sample source	Brain-relevant sample characteristics	Brain imaging methods and measurements	Statistically controlled confounding variables	Selected findings and conclusions	Authors
Whole brain GM WM CSF	M > F	18 untreated early-onset GD Hom MtF 19 Het F 19 Het M MtF: 24.71 ± 8.15 Het F:33  ± 8.23 Het M: 31.94 ± 6.11	Hospital Clinic, Barcelona, Spain	Untreated early-onset GD MtFs	3 T Siemens Trio SIENAX Measurement ICV	Age SD	MtF = M: ICV, GM, WM, CSF Conclusions In MtF ICV and GM, WM, and CSF compartments are masculine	Rametti et al. (2011b)
Whole brain	M > F	11 Untreated androphilic MtF adolescents: 44 M and 52 F MtFs: 13.77  ± 2.42 M: 16.42  ± 2.75 F: 16.29 ± 2.96	Center of Expertise on Gender Dysphoria ,VU University, Amsterdam, Netherlands	Untreated adolescent MtFs	VBM Measurement Intracranial volume	Tanner stage	MF>F Conclusions ICV masculine	Hoekzema et al. (2015)

ICV intracranial volume, GM gray matter, WM white matter, CSF cerebrospinal fluid (includes ventricles and cisterns), FDR false discovery rate, VBM voxel-based morphometry, SD sex differences, M male, F female, Ss subjects, MtF male-to-female transsexuals, Hom homosexual, Het heterosexual