-In a world where we don't _have_ magical perfect sex-change technology, but we _do_ have hormone replacement therapy and various surgical methods, you actually end up with _four_ clusters: females, males, masculinized females (a.k.a. trans men), and feminized males (a.k.a. trans women).
+In a world where we don't _have_ magical perfect sex-change technology, but we _do_ have hormone replacement therapy and various surgical methods, you actually end up with _four_ clusters: females (F), males (M), masculinized females a.k.a. trans men (FtM), and feminized males a.k.a. trans women (MtF). I _don't_ have a "clean" philosophical answer as to in what contexts one should prefer to use a {F, MtF}/{M, FtM} category system (treating trans people as their social gender) rather than a {F, FtM}/{M, MtF} system (considering trans people as their [developmental sex](/2019/Sep/terminology-proposal-developmental-sex/)), because that's a complicated semi-empirical, semi-value question about which aspects of reality are most relevant to what you're trying think about in that context, but I do need _the language with which to write this sentence_, which is about _modeling reality_, and not about marginalization or respect.