+But at the time, this was merely _very confusing_. I left [a careful comment in the Facebook thread](/images/facebook_etle_comment.png) (with the obligatory "speaking only for myself; I obviously know that I can't say anything about anyone else's experience" [disclaimer](https://www.overcomingbias.com/2008/06/against-disclai.html)), quietly puzzled at what Yudkowsky could _possibly_ be thinking ...
+
+A month later, I moved out of my mom's house in [Walnut Creek](https://en.wikipedia.org/wiki/Walnut_Creek,_California) to go live with a new roommate in an apartment on the correct side of the [Caldecott tunnel](https://en.wikipedia.org/wiki/Caldecott_Tunnel), in [Berkeley](https://en.wikipedia.org/wiki/Berkeley,_California): closer to other people in the robot-cult scene and with a shorter train ride to my coding dayjob in San Francisco.
+
+(I would later change my mind about which side of the tunnel is the correct one.)
+
+In Berkeley, I met some really interesting people who seemed quite similar to me along a lot of dimensions, but also very different along some other dimensions having to do with how they were currently living their life! (I see where the pattern-matching faculties in Yudkowsky's brain got that 20% figure from.) This prompted me to do a little bit more reading in some corners of the literature that I had certainly _heard of_, but hadn't already mastered and taken seriously in the previous twelve years of reading everything I could about sex and gender and transgender and feminism and evopsych. (Kay Brown's blog, [_On the Science of Changing Sex_](https://sillyolme.wordpress.com/), was especially helpful.)
+
+Between the reading, and a series of increasingly frustrating private conversations, I gradually became increasingly persuaded that Blanchard _wasn't_ dumb and wrong, that his taxonomy of male-to-female transsexualism is _basically_ correct, at least as a first approximation. So far this story has just been about _my_ experience, and not anyone's theory of transsexualism (which I had assumed for years couldn't possibly apply to me), so let me take a moment to explain the theory now.
+
+(With the caveated understanding that psychology is complicated and there's more to be said about what "as a first approximation" is even supposed to mean, but I need a few paragraphs to talk about the _simple_ version of the theory that makes _pretty good_ predictions on _average_, before I can elaborate on more complicated theories that might make even better predictions including on cases that diverge from average.)
+
+The idea is that male-to-female transsexualism isn't actually one phenomenon; it's two completely different phenomena that don't actually have anything to do with each other, except for the (perhaps) indicated treatment of HRT, surgery, and social transition. (Compare to how different medical conditions might happen to respond to the same drug.)
+
+In one taxon, the "early-onset" type, you have same-sex-attracted males who have just been extremely feminine (in social behavior, interests, _&c._) their entire lives, in a way that causes huge social problems for them—the far tail of effeminate gay men who end up fitting into Society better as straight women. _That's_ where the "woman trapped inside a man's body" trope comes from. [This one probably _is_ a brain-intersex condition.](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3180619/)
+
+That story is pretty intuitive. Were an alien AI to be informed of the fact that, among humans, some fraction of males elect to undergo medical interventions to resememble females and aspire to be perceived as females socially, "brain-intersex condition such that they already behave like females" would probably be its top hypothesis for the cause of such behavior, just on priors.
+
+Suppose our alien AI were to be informed that many of the human males seeking to become female (as far as the technology can manage) do _not_ fit the clinical profile of the early-onset type—it looks like there's a separate "late-onset" type or types. If you [didn't have enough data to _prove_ anything, but you had to guess](https://www.lesswrong.com/posts/xTyuQ3cgsPjifr7oj/faster-than-science), what would be your _second_ hypothesis for how this behavior might arise?
+
+What's the _usual_ reason for males to be obsessed with female bodies?
+
+So, yeah. Basically, I think a _substantial majority_ of trans women under modern conditions in Western countries are, essentially, guys like me who were _less self-aware about what the thing actually is_.
+
+So, I realize this is an inflamatory and (far more importantly) _surprising_ claim. Obviously, I don't have introspective access into other people's minds. If someone claims to have an internal sense of her own gender that doesn't match her assigned sex at birth, on what evidence could I _possibly_ have the _astounding_ arrogance to reply, "No, I think you're really just a perverted male like me"?
+
+Actually, lots. To arbitrarily pick one particularly vivid exhibit, in April 2018, the [/r/MtF subreddit](https://www.reddit.com/r/MtF/) (which currently has 100,000 subscribers) [posted a link to a poll: "Did you have a gender/body swap/transformation "fetish" (or similar) before you realised you were trans?"](https://archive.is/uswsz). The [results](https://strawpoll.com/5p7y96x2/r): [_82%_ said Yes](/images/did_you_have-reddit_poll.png). [Top comment in the thread](https://archive.is/c7YFG), with over 230 karma: "I spent a long time in the 'it's probably just a fetish' camp".
+
+Certainly, 82% is not 100%! (But 82% is evidence for my claim that a _substantial majority_ of trans women under modern conditions in Western countries are essentially guys like me.) Certainly, you could argue that Reddit has a sampling bias such that poll results and karma scores from /r/MtF fail to match the distribution of opinion among real-world MtFs. But if you don't take the gender-identity story as a _axiom_ and [_actually look_](https://www.lesswrong.com/posts/SA79JMXKWke32A3hG/original-seeing) at the _details_ of what people say and do, these kinds of observations are _not hard to find_. You could [fill an entire subreddit with them](https://archive.is/ezENv) (and then move it to [independent](https://ovarit.com/o/ItsAFetish/) [platforms](https://saidit.net/s/itsafetish/) when the original gets [banned for "promoting hate"](https://www.reddit.com/r/itsafetish/)).
+
+Reddit isn't "scientific" enough for you? Fine. The scientific literature says the same thing. [Blanchard 1985](/papers/blanchard-typology_of_mtf_transsexualism.pdf): 73% of non-exclusively-androphilic transsexuals acknowledged some history of erotic cross-dressing. (Unfortunately, a lot of the classic studies specifically asked about cross-_dressing_, but the underlying desire isn't about clothes.) [Lawrence 2005](/papers/lawrence-sexuality_before_and_after_mtf_srs.pdf): of trans women who had female partners before sexual reassignment surgery, 90% reported a history of autogynephilic arousal. [Smith _et al._ 2005](/papers/smith_et_al-transsexual_subtypes_clinical_and_theoretical_significance.pdf): 64% of non-homosexual MtFs (excluding the "missing" and "N/A" responses) reported arousal while cross-dressing during adolescence. (A lot of the classic literature says "non-homosexual", which is with respect to natal sex; the idea is that self-identified bisexuals are still in the late-onset taxon.) [Nuttbrock _et al._ 2011](/papers/nuttbrock_et_al-a_further_assessment.pdf): lifetime prevalence of transvestic fetishism among non-homosexual MtFs was 69%. (For a more detailed literature review, see [Kay Brown's blog](https://sillyolme.wordpress.com/faq-on-the-science/) or the first two chapters of [Anne Lawrence's _Men Trapped in Men's Bodies: Narratives of Autogynephilic Transsexualism_](https://surveyanon.files.wordpress.com/2017/07/men-trapped-in-mens-bodies_book.pdf).)
+
+Peer-reviewed scientific papers aren't enough for you? (They could be cherry-picked; there are lots of scientific journals, and no doubt a lot of bad science slips through the cracks of the review process.) Want something more indicative of a consensus among practitioners? Fine. The [_Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition_](https://en.wikipedia.org/wiki/DSM-5) (the definitive taxonomic handbook of the American Psychiatric Association) [says the same thing](https://sillyolme.wordpress.com/2021/02/06/american-psychiatric-association-supports-the-two-type-transsexual-taxonomy/) in [its section on gender dysphoria](/papers/DSM-V-gender_dysphoria_section.pdf) ([ICD-10-CM codes](https://en.wikipedia.org/wiki/ICD-10-CM) F64.1 and F64.2):
+
+> In both adolescent and adult natal males, there are two broad trajectories for development of gender dysphoria: early onset and late onset. _Early-onset gender dysphoria_ starts in childhood and continues into adolescence and adulthood; or, there is an intermittent period in which the gender dysphoria desists and these individuals self-identify as gay or homosexual, followed by recurrence of gender dysphoria. _Late-onset gender dysphoria_ occurs around puberty or much later in life. Some of these individuals report having had a desire to be of the other gender in childhood that was not expressed verbally to others. Others do not recall any signs of childhood gender dysphoria. For adolescent males with late-onset gender dysphoria, parents often report surprise because they did not see signs of gender dysphoria in childhood. Adolescent and adult natal males with early-onset gender dysphoria are almost always sexually attracted to men (androphilic). Adolescents and adults with late-onset gender dysphoria **frequently engage in transvestic behavior with sexual excitement.**
+
+(Bolding mine.)
+
+Or consider Anne Vitale's ["The Gender Variant Phenomenon—A Developmental Review"](http://www.avitale.com/developmentalreview.htm), which makes the _same_ observations as Blanchard-and-friends and arrives at essentially the _same_ two-type taxonomy of MtF, but dressed up in socially-desirable language—
+
+> As sexual maturity advances, Group Three, cloistered gender dysphoric boys, often combine excessive masturbation (one individual reported masturbating up to 5 and even 6 times a day) with an increase in secret cross-dressing activity to release anxiety.
+
+Got that? They _often combine excessive masturbation_ with an _increase in secret cross-dressing activity_ to _release anxiety_—their terrible, terrible _gender expression deprivation anxiety!_
+
+Don't trust scientists or clinicians? Me neither! (Especially [not clinicians](/2017/Jun/memoirs-of-my-recent-madness-part-i-the-unanswerable-words/).) Want first-person accounts from trans women themselves? Me too! And there's lots!
+
+Consider this passage from Dierdre McCloskey's memoir _Crossing_, writing in the third person about her decades identifying as a heterosexual crossdresser before transitioning at age 53 (bolding mine):
+
+> He had been doing it ten times a month through four decades, whenever possible, though in the closet. The quantifying economist made the calculation: _About five thousand episodes_. [...] At fifty-two Donald accepted crossdressing as part of who he was. True, if before the realization that he could cross all the way someone had offered a pill to stop the occasional cross-dressing, he would have accepted, since it was mildly distracting—though hardly time consuming. **Until the spring of 1995 each of the five thousand episodes was associated with quick, male sex.**
+
+Or consider this passage from Julia Serano's _Whipping Girl_ (I know I [keep](/2017/Dec/lesser-known-demand-curves/) [referencing](/2020/Dec/crossing-the-line/) [this](/2021/May/sexual-dimorphism-in-the-sequences-in-relation-to-my-gender-problems/#whipping-girl) book, but it's _so representative_ of the dominant strain of trans activism, and I'm never going to get over the [Fridge Logic](https://tvtropes.org/pmwiki/pmwiki.php/Main/FridgeLogic) of the all [the blatant clues that I somehow missed in 2007](/2016/Sep/apophenia/))—
+
+> There was also a period of time when I embraced the word "pervert" and viewed my desire to be female as some sort of sexual kink. But after exploring that path, it became obvious that explanation could not account for the vast majority of instances when I thought about being female in a nonsexual context.