>>41313191 (OP)
The term "gender identity" was coined by John Money in the 1960s. Around 1950 Money had begun work with intersex kids--at the time called "hermaphrodites" and "pseudo hermaphrodites". The "hermaphrodite" medical category included far fewer conditions than the modern "disorders of sex development" (DSD) category does. A lot of what is categorized under DSD today was not included in the hermaphrodite category.
John Money, starting in the 1950s, began the trend of surgically & hormonally altering "hermaphrodite" children. He believed that their "gender identity"--a term he himself coined--was purely socially imposed and that altering the genitals and secondary sex traits would be sufficient to induce the "gender identity" associated with that sex. Keeping this secret from the child was also important--they were never to know they were a "hermaphrodite". Deceiving the child and everyone the child interacted with, even recommending doctors withhold medical records and information, is the foundation of "gender identity"; lying to the subject and to everyone in the environment is the foundation.
This abuse of intersex kids went on from 1950 to the 2000s. It ended because of David Reimer.
David Reimer is the boy who was not intersex, but lost most of his penis during a circumcision incident. He was brought to money due to Money's so-called "expertise". Money's recommendation was to remove David's testes and perform a vaginoplasty, then lie to him for the rest of his life, as he had recommended for many intersex kids. Many of Money's past intersex patients had spoken about the abuse suffered under his medical protocols and in the 90s they began reaching each other due to the internet. This is where the term "intersex" comes from; not the medical system, but "hermaphrodite" activism that included renaming themselves to try to distance from the abusive control the medical system assumed over them and their treatment options.
Transgenderism is full of John Money.