So it seems like some on here think that in the past there were two types of men in dresses? The "I get a kick out of it" cross-dressing transvestites, and the really unusual, dysphoric ones who had surgery? Is that what people are saying? I am not sure how true that used to be, but I am confident not that true and certainly not true now.
Ok, so I mostly defer to Az Hakeem, but some of my spin on it might be different.
On paraphilias I don't go by how unusual the philia is, but by its intensity. This would probably be seen as crude by sexologists, but I do a sliding scale: sexual preference (we all have that, it could be height or hair colour or body shape or any manner of things) > fetish (where the preference goes from a nice to have to a necessity; the difference between liking a shapely ankle and not being able to achieve arousal without some kind of elaborate footplay) > paraphilia (when it becomes so overwhelming that it takes over your civilian life).
I've never believed the story some women tell, that only men have fetishes, but I do think paraphilias are an overwhelmingly male thing. Women are just much less likely to autistically fixate on some specific thing to the extent that it dominates their lives.
Having got that out of the way...
I don't disagree with the distinction Az draws between the transvestic fetishist and the autogynephile, but I see a definite overlap between them. I want to say that I see AGP as a development and escalation of transvestism. I find it hard to think of anyone developing AGP without first going through the stage of transvestism, though most transvestites never pass through to the AGP stage.
I don't think I believe in "true trans", but I'm reluctant to reduce all of it to fetishism because I've known a few old-fashioned homosexual transsexuals who didn't seem to be in it for fetishistic arousal, but simply because - however they came by their body dysmorphia - presenting in a female style was the only way they could feel comfortable. I don't feel that their condition is the same as AGP.
But, in the same way that gay men are massively outnumbered by straight men, your dysphoric homosexual transsexual will be massively outnumbered by heterosexual transvestite fetishists, and it's obvious the latter make up the large majority of TIMs these days. Whereas the #bekinders work on an assumption, or wishful thinking more like, that the dysphoric HSTS is the norm.
And again that becomes a problem because public policy for decades has been based on an idea of the dysphoric HSTS as the norm, which simply doesn't apply today.
Obviously I'm not a clinician and this is just my unscientific way of thinking things through. But I think the key is how fetishes escalate into paraphilias.