During this time, people who were assigned male at birth (AMAB) and expressed gender nonconformity were often classified into one of two subgroups.
[2] Harry Benjamin created the Sex Orientation Scale (SOS) to classify and understand various forms and subtypes of transvestism and transsexualism in transfeminine populations.
"[3] Benjamin added a caveat: "It has been the intention here to point out the possibility of several conceptions and classifications of the transvestitic and the transsexual phenomenon.
Future studies and observations may decide which one is likely to come closest to the truth and in this way a possible understanding of the etiology may be gained.
Interestingly, in the major revision of the DSM, DSM-III-R, they were placed in the category "Disorders Usually First Evident in Infancy, Childhood or Adolescence".
Under this system, every health condition can be assigned to a unique category and given a code, up to six characters long.
This system is designed to promote international comparability in the collection, processing, classification, and presentation of these statistics.
In the eleventh revision of the ICD, published in June 2018,[13] F64 Gender identity disorders[14] and F65.1 Fetishistic Transvestism were removed,[15] among other sexual practices, that used to be referred to as paraphilias.
[17] The major paradigm shift is reflected in the last sentence from code HA60: "Gender variant behavior and preferences alone are not a basis for assigning the diagnosis."
The issues with Blanchard's work were again the subject of criticism with the publication of Bailey's The Man Who Would Be Queen in 2003.
[20] A 2016 review found support for the predictions of Blanchard's typology that androphilic and gynephilic trans women have different brain phenotypes.
A much better verification of the hypothesis could be supplied by a specifically designed study including homosexual and nonhomosexual MtFs."