Transgender people are less than .01% of the population.
What percentage of the population would you guess is made up of people who think they are Jesus?
Incidentally, more recent studies tend to find much higher proportions of transgender people, which presumably is not unrelated to what you describe as its being "the currently fashionable form of insanity". I don't think you get to claim both <0.01% and that it was a lot fewer 50 years ago.
Terminology note: If I understand what is going on here, VoiceOfRa is probably using transgender to mean people who want to change male-to-female or female-to-male, and are making a serious attempt at it (sexual reassignment surgery, hormone therapy, or the like). This is not an uncommon usage, but is not the most precise usage; this would more specifically be referred to transsexual.
This may be relevant because the stats quoted appear to apply specifically to transsexuals, not to the larger class transgender (which includes anyone who feels that that the...
There are some long lists of false beliefs that programmers hold. isn't because programmers are especially likely to be more wrong than anyone else, it's just that programming offers a better opportunity than most people get to find out how incomplete their model of the world is.
I'm posting about this here, not just because this information has a decent chance of being both entertaining and useful, but because LWers try to figure things out from relatively simple principles-- who knows what simplifying assumptions might be tripping us up?
The classic (and I think the first) was about names. There have been a few more lists created since then.
Time. And time zones. Crowd-sourced time errors.
Addresses. Possibly more about addresses. I haven't compared the lists.
Gender. This is so short I assume it's seriously incomplete.
Networks. Weirdly, there is no list of falsehoods programmers believe about html (or at least a fast search didn't turn anything up). Don't trust the words in the url.
Distributed computing Build systems.
Poem about character conversion.
I got started on the subject because of this about testing your code, which was posted by Andrew Ducker.