+The argument goes: it might be easy to _imagine_ changing sex and refer to the idea in a short English sentence, but the real physical world has implementation details, and the implementation details aren't filled in by the short English sentence. The human body, including the brain, is an enormously complex integrated organism; there's no [plug-and-play](https://en.wikipedia.org/wiki/Plug_and_play) architecture by which you can just swap your brain into a new body and have everything Just Work without re-mapping the connections in your motor cortex. And even that's not _really_ a sex change, as far as the whole integrated system is concerned—
+
+[TODO: include more blockquote here]
+
+> Remapping the connections from the remapped somatic areas to the pleasure center will ... give you a vagina-shaped penis, more or less. That doesn't make you a woman. You'd still be attracted to girls, and no, that would not make you a lesbian; it would make you a normal, masculine man wearing a female body like a suit of clothing.
+
+But, well ... I mean, um ...
+
+(I still really don't want to be blogging about this, but _somebody has to and no one else will_)
+
+From the standpoint of my secret erotic fantasy, "normal, masculine man wearing a female body like a suit of clothing" is actually a _great_ outcome—the _ideal_ outcome. Let me explain.
+
+The main plot of my secret erotic fantasy accomodates many frame stories, but I tend to prefer those that invoke the [literary genre of science](https://www.lesswrong.com/posts/4Bwr6s9dofvqPWakn/science-as-attire), and posit technology indistinguishable from magic rather than magic _simpliciter_.
+
+So imagine having something like the transporter in _Star Trek_, but you re-materialize with the body of someone else, rather than your original body—a little booth I could walk in, dissolve in a tingly glowy special effect for a few seconds, and walk out looking like (say) [Nana Visitor (circa 1998)](https://memory-alpha.fandom.com/wiki/Kay_Eaton?file=Kay_Eaton.jpg). (In the folklore of [female-transformation erotica](/2016/Oct/exactly-what-it-says-on-the-tin/), this machine is often called the ["morphic adaptation unit"](https://www.cyoc.net/interactives/chapter_115321.html).)
+
+This high-level description of a hypothetical fantasy technology leaves some details unspecified—not just the _how_, but the _what_. What would the indistinguishable-from-magical transformation booth do to my brain? [As a preference-revealing thought experiment](https://www.lesswrong.com/posts/DdEKcS6JcW7ordZqQ/not-taking-over-the-world), what would I _want_ it to do, if I can't change [the basic nature of reality](https://www.lesswrong.com/posts/tPqQdLCuxanjhoaNs/reductionism), but if engineering practicalities weren't a constraint? (That is, I'm allowed to posit any atom-configuration without having to worry about how you would get all the atoms in the right place, but I'm not allowed to posit tethering my immortal soul to a new body, because [souls](https://www.lesswrong.com/posts/u6JzcFtPGiznFgDxP/excluding-the-supernatural) [aren't](https://www.lesswrong.com/posts/7Au7kvRAPREm3ADcK/psychic-powers) [real](https://www.lesswrong.com/posts/fdEWWr8St59bXLbQr/zombies-zombies).)
+
+The anti-plug-and-play argument makes me confident that it would have to change _something_ about my mind in order to integrate it with a new female body—if nothing else, my unmodified brain doesn't physically _fit_ inside Nana Visitor's skull. ([One meta-analysis puts the sex difference in intracranial volume and brain volume at](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969295/) a gaping [Cohen's _d_](/2019/Sep/does-general-intelligence-deflate-standardized-effect-sizes-of-cognitive-sex-differences/) ≈ 3.0 and 2.1, respectively, and Visitor doesn't look like she has an unusually large head.)
+
+Fine—we're assuming that difficulty away and stipulating that the magical transformation booth can make the _minimal_ changes necessary to put my brain in a female body, and have it fit, and have all the motor-connection/body-mapping stuff line up so that I can move and talk normally in a body that feels like mine.
+
+I want this more than I can say. But is that _all_ I want? What about all the _other_ sex differences in the brain? Male brains are more lateralized—doing [relatively more communication within hemispheres rather than between](https://www.pnas.org/content/111/2/823); there are language tasks that women and men perform equally well on, but [men's brains use only the _left_ inferior frontal gyrus, whereas women's use both](/papers/shaywitz-et_al-sex_differences_in_the_functional_organization_of_the_brain_for_language.pdf). Women have a relatively thicker corpus callosum; men have a relatively larger amygdala. Fetal testosterone levels [increase the amount of gray matter in posterior lateral orbitofrontal cortex, but decrease the gray matter in Wernicke's area](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306238/) ...
+
+Do I want the magical transformation technology to fix all that, too?
+
+Do I have _any idea_ what it would even _mean_ to fix all that, without spending multiple lifetimes studying neuroscience?
+
+I think I have just enough language to _start_ to talk about what it would mean.
+
+[TODO: rewrite this whole section to be more focused on _just_ explaining the math language needed to explain how the transformation mapping would work, using face and height as "easy" examples]
+
+People are [verifiably very good at recognizing sex from (hair covered, males clean-shaven) photographs of people's faces](/papers/bruce_et_al-sex_discrimination_how_do_we_tell.pdf) (96% accuracy, which is the equivalent of _d_ ≈ 3.5), but we don't have direct introspective access into what _specific_ features our brains are using to do it; we just look, and _somehow_ know. The differences are real, but it's not a matter of any single measurement: [covering up the nose makes people slower and slightly worse at sexing faces, but people don't do better than chance at guessing sex from photos of noses alone](/papers/roberts-bruce-feature_saliency_in_judging_the_sex_and_familiarity_of_faces.pdf).
+
+[TODO: Mathematically,
+Joel et al. and response—maybe in next paragraph
+Beyond the Binary: https://www.pnas.org/content/112/50/15468
+http://cogprints.org/10046/1/Delgiudice_etal_critique_joel_2015.pdf
+
+http://zackmdavis.net/blog/2019/05/the-typical-set/
+> once you draw a boundary around a group, the mind starts trying to harvest similarities from the group. And unfortunately the human pattern-detectors seem to operate in such overdrive that we see patterns whether they're there or not; a weakly negative correlation can be mistaken for a strong positive one with a bit of selective memory.
+https://www.lesswrong.com/posts/veN86cBhoe7mBxXLk/categorizing-has-consequences
+[a higher-dimensional statistical regularity in the _conjunction_ of many variables](https://www.lesswrong.com/posts/cu7YY7WdgJBs3DpmJ/the-univariate-fallacy-1)
+96.8% classification from MRI https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6374327/
+]
+[talk about mapping from one distribution to another: e.g. height]