Introduction to Blanchard’s two-type model of male-to-female transsexuals
The most accurate description we have of the causes of male gender dysphoria and desire to transition comes from the work of Ray Blanchard. He identifies two distinct etiologies of MtF desire to transition:
The first type are homosexual transsexuals (HSTS). These will show female-typical behaviors and preferences from an early age, tend to transition younger, and show shifts towards the female average in many physical and psychological traits. This is likely due to prenatal under-masculinization. They will be shorter, have a more naturally feminine build, have female-typical digit ratios, brain fMRI results shifted towards the female cluster, female-typical rates of violent crime, and female-typical hobbies and interests. HSTS transition primarily in order to attract more masculine male partners than they could as gay men. Many are very invested in the idea of having straight boyfriends.
The second type are autogynephiles (AGPs). These are heterosexual men with a cognitive trait that causes them to internalize their sexuality. They are attracted to women, but this is aimed at themselves, so they feel ugly in male bodies and excited/satisfied by the thought of having a female body, wearing women’s clothes, occupying traditionally feminine roles, etc. Even though they are orientationally heterosexual (not turned on by pictures of naked men, when measured in laboratory conditions) they sometimes have sex with men to fulfill their desire to occupy a female sexual role. They sometimes even marry them. But they exhibit none of the natural feminization that HSTS do. They have male-typical brain scans, male-typical height and digit ratios, male-typical (or worse) levels of criminality, and male-typical interests. They have very high rates of autism and personality disorders, and high average IQs. I myself am an autogynephilic MtFtM detransitioner.