Kurt Freund was a Czech-Canadian physician and sexologist best known for developing penile phallometry which is measurement of sexual arousal in males using a device. His area of work was in sexual disorders such as pedophilia and exhibitionism and in the late 1960’s he ended up at the now named CAMH (the center for addiction and mental health) in Toronto.
In his native Czechoslovakia, Freund was tasked with using penile plethysmography to detect recruits attempting to avoid serving in the military by falsely claiming to be homosexual since this was grounds for being dismissed from service at that time. However, the main focus of his work was detecting and diagnosing sex offenders with the aim of establishing appropriate treatment guidelines. Freund was also involved in administering aversion therapy to homosexuals which, to no one’s surprise this day and age, proved to be futile.
Freund’s work influenced Ray Blanchard who has dismissively said of him:
“he was not my academic advisor, and I have nowhere described him as such. He was an (informal) mentor, and he was responsible for my becoming interested in research on paraphilias, gender identity disorders, and sexual orientation” (note the use of the outdated term gender identity disorder)
It was in fact Kurt Freund who first distinguished between two proposed types of transsexuals in a 1982 research article, theorizing that the "homosexual" type was qualitatively different from the so-called "heterosexual males" with gender dysphoria. Later, Ray Blanchard invented the term "autogynephilia" in 1989 to describe this latter proposed type and theorize their disorder was rooted in sexual deviance and a love of their own image as women.
Where this whole concept has gotten into trouble is the lack of an understanding of where the arousal originates and the inability to prove that AGP is correct. This has been a sore point for Blanchard whose remaining career has been relegated to Twitter.
Could the arousal be a symptom of gender dysphoria? Of course it could which is why this line of theorizing proved to be a dead end in terms of having hard science to back it up. An explanation for the origins of transsexualism still awaits but this serves as a cautionary tale of how we can misfire and even, for a time, fool other experts into thinking that there is an answer despite the lack of definitive science.
Verifying that there is arousal is hardly a challenge and is its own reward (we don't need a pseudo term for that). Understanding its origins is where the true science lies n'est-ce pas?