Researchers have tried to count trans people, but not proved particularly good at it.
In 2015, researchers analysed 27 previous studies on how many people are trans. They found there were 9.2 people per 100,000 population who sought surgery or hormones, but the 95% confidence interval was that this figure was between 4.9 and 13.6. It could be as little as half of the headline figure. The headline figure is 0.01% of the population, which is about what I estimated.
The figure that sought hormones or surgery was greater than the figure with a trans-related diagnosis (transsexualism, gender identity disorder or gender dysphoria): that figure was 6.8 (4.6-9.1) per 100,000.
How many people self-report a transgender identity? 355 (144-566) per 100,000. I got this meta-analysis from an anti-trans hate site, which used it to scaremonger about trans women in women’s spaces with those oh-so-scary penises. 2.6% seek surgery. However, that does not indicate what the others do. Not all of us transition. Many of those who report a transgender identity might be firmly closeted, without any intention to present in their true gender except when alone or with one or two trusted friends. Possibly the only trans women in women’s spaces are those who have had, or are seeking, hormones and surgery.
However, the study shows that in order to count trans people you need a specific definition of what a trans person is, because the results for different definitions may range by orders of magnitude.
Six studies only considered people who sought or received genital surgery, and were published between 1968 and 2014, on subjects from the US, Europe and Singapore. A 1968 study estimated one in 100,000 MTFs, one in 400,000 FTMs, sought surgery, but then the concept of trans people was not widely known. There has been a continual increase in the number of people seeking medical transition, by a factor of ten or more since 2000.
A Belgian study asked plastic surgeons how many people had undergone surgery from 1985 to 2003, and found 7.74 trans women per 100,000 women. That is, in 2003 the Belgian figure of those who had had surgery was already approaching the 9.2 figure the meta-analysis gave in 2016 for the number who had had surgery or hormones, or were seeking it. To me, that indicates the 9.2 figure is a substantial underestimate. An Italian study in 2008 found 424 M-F surgeries since 1992, 1.5/100,000, and thought the figure being lower than in other countries could be explained either by missing data or cultural factors. Yet this figure, too, was used to calculate the 9.2 figure.
In 1986, a Singapore study reported 35.2/100,000 M-F. They reported cultural acceptance and established surgical procedures as reasons for the higher figure.
In Iran, between 4,000 and 6,000 gay men and lesbians have been executed for homosexuality since 1979. The Ayatollah Khomeini, however, gave a judgment that some people were transsexual, and between 2002 and 2009 a study identified 281 people having genital surgery. I have heard it suggested that gay people in Iran would transition to avoid execution, but that is not confirmed by the prevalence figure, 0.7/100,000, which is much less than the prevalence elsewhere. The Supreme Leader might have said it’s OK to transition, but that does not mean society will accept it.
Assessing prevalence of transgender identity, it depends what you mean by transgender identity. In 2007-2009 a study in Massachusetts asked, “Some people describe themselves as transgender when the experience a different gender identity from their sex at birth. For example, a person born into a male body, but who feels female or lives as a woman. Do you consider yourself to be transgender?” That gave 500/100,000. “A person born into a male body but who feels female” might never cross-dress at all. The words “For example” make the definition stretchier, and the number larger.
A 2010 survey considered US young adults, asking about sex assigned at birth then gender identity. 26 identified as the other gender, transgender, or other, which is 0.33% (330/100,000).
In 1991, a German study estimated 2.1/100,000 trans people had changed their name to one of the other sex. That would be the number who had socially transitioned, so the number seeking surgery is much the same as the number out and about as trans.
In New Zealand, you can change your passport between M, F and X. By 2008 there had been 385 X. My passport says F, and I would not want an X designation.
The authors write, “With these considerations in mind, the current communication should not be viewed as an attempt to obtain an average measure of transgender prevalence. Rather our analyses aimed to explore patterns of the reported estimates, and to perform an assessment of the extent and sources of agreement and disagreement across studies.” That is, the meta-analysis does not tell us how many trans people there are, or how many seek surgery, but are a comment on the quality of the data. So the hate site is debunked: the authors specifically say that their data should not be used to make such assertions.
The highest figure was 700/100,000 self-reporting transgender identity. This is less than 1%, and does not justify the rage and energy of anti-trans campaigners such as Liz Truss. At the same time it is probably much greater than the number of trans women who ever enter women’s spaces.
I hope the British census will do better.
The meta-analysis is here. The study has been peer-reviewed and published, but I could only access this, which is a pre-print. I did not know what a pre-print was before Covid. I have a new page on various attempts to count trans people.