Individuals with CAH are typically subjected to medical interventions including prenatal hormone treatment[12] and postnatal genital reconstructive surgeries.
Research has shown that people with CAH and XX chromosomes will be more likely to experience same-sex attraction,[12] and at least 5.2% of these individuals develop serious gender dysphoria.
Individuals with this condition are typically assigned female and raised as girls due to their feminine appearance at a young age.
Scientists speculate that the definition of masculine characteristics during puberty and the increased social status afforded to men are two possible motivations for a female-to-male transition.
[15][16] A first-of-its-kind study by Zhou et al. (1995) found that in the bed nucleus of the stria terminalis (BSTc), a region of the brain known for sex and anxiety responses (and which is affected by prenatal androgens),[17] cadavers of six trans women had female-normal BSTc size, similar to the study's cadavers of cisgender women.
[21][19] In the textbook Adult Psychopathology and Diagnosis, 7th edition, Lawrence and Zucker suggested that the BSTc may not be a valid biomarker for gender incongruence, as differences in size could be caused by gender-affirming hormone therapy or paraphilias, and might not occur in homosexual transsexuals.
[24] In 2008, Garcia-Falgueras & Swaab discovered that the interstitial nucleus of the anterior hypothalamus (INAH-3), part of the hypothalamic uncinate nucleus, had properties similar to the BSTc with respect to sexual dimorphism and gender incongruence, likewise in line with the trans individuals’ declared genders and likewise regardless of if hormonal transition had occurred or not.
[scientific citation needed] Rametti et al. (2011) studied 18 trans men who had not undergone hormone therapy using diffusion tensor imaging (DTI), an MRI technique which allows visualizing white matter, the structure of which is sexually dimorphic.
Rametti et al. discovered that the trans men's white matter, compared to 19 cisgender gynephilic females, showed higher fractional anisotropy values in posterior part of the right SLF, the forceps minor and corticospinal tract".
(...) These sex reversals were found not to be influenced by circulating hormone levels in adulthood, and seem thus to have arisen during development" and that "All observations that support the neurobiological theory about the origin of transsexuality, i.e. that it is the sizes, the neuron numbers, and the functions and connectivity of brain structures, not the sex of their sexual organs, birth certificates or passports, that match their gender identities".
"[2] A 2019 review in Neuropsychopharmacology found that among transgender individuals meeting diagnostic criteria for gender dysphoria, "cortical thickness, gray matter volume, white matter microstructure, structural connectivity, and corpus callosum shape have been found to be more similar to cisgender control subjects of the same preferred gender compared with those of the same natal sex.
"[32] A 2021 review of brain studies published in the Archives of Sexual Behavior found that "although the majority of neuroanatomical, neurophysiological, and neurometabolic features" in transgender people "resemble those of their natal sex rather than those of their experienced gender", for trans women they found feminine and demasculinized traits, and vice versa for trans men.
They stated that due to limitations and conflicting results in the studies that had been done, they could not draw general conclusions or identify-specific features that consistently differed between cisgender and transgender people.
[2] For trans men, research indicates that those with early-onset gender dysphoria and who are gynephilic have brains that generally correspond to their assigned sex, but that they have their own phenotype with respect to cortical thickness, subcortical structures, and white matter microstructure, especially in the right hemisphere.
[2] MRI taken on gynephilic trans women have likewise shown differences in the brain from non-trans people, though in ways not directly related to sexual dimorphism.
It is common for people assigned male at birth who have late-onset gender dysphoria to experience sexual excitement from cross-dressing.
[citation needed] Blanchard's theory has received support from J. Michael Bailey, Anne Lawrence, and James Cantor.
[40] Blanchard argued that there are significant differences between the two groups, including sexuality, age of transition, ethnicity, IQ, fetishism, and quality of adjustment.