Your comment is very welcome and appreciated and I would've upvoted it to be the first comment people see if I could, but my 100% vote is still tiny.
The term transsexual was used in all the studies I read, so it would be a bit odd (condescending?) to change or update their term for them, or to vacillate depending on when I was using it as opposed to when I was elaborating on the studies.
You gave a very detailed reply and I will certainly refer to it (maybe even reference it) in the future. I'll most probably be using the more accepted terms from now on.
I hope a writer is still allowed some leeway for purposes of flow or joking. I wouldn't mind someone saying 'a white' to make content somehow more snappy or to make a subtle reference to something cultural or a kind of joke.
Thanks for reading an 'old' article. I often do that - since an article's worth doesn't depend on whether its payout period is over - but not many others do.