Fausto-Sterling seems to be loose with data. In The Five Sexes she cites Money as the source for upwards of 4% of the population being intersexual.
Money denied the claim here (last page) https://www.researchgate.net/publication/239657377_The_Five_...
Later she revised to 1.7% in this paper with some fairly loose definitions of what constitutes "frequency of deviation from the idea female or male" http://www.ncbi.nlm.nih.gov.sci-hub.tw/pubmed/11534012
If you dig into the 1.7% figure, 87% of it comes from late onset CAH. Problematic, as Late onset CAH is very similar to PCOS, which affects 5-10% of the population and was excluded. Both fit her definition of deviation from the sexual idea (hirtuisim, infertility) https://i.imgur.com/BYi5dem.png
> In a paper entitled "The Five Sexes", in which, according to her, "I had intended to be provocative, but I had also written with tongue firmly in cheek." Fausto-Sterling laid out a thought experiment considering an alternative model of gender containing five sexes: male, female, merm, ferm, and herm. This thought experiment was interpreted by some as a serious proposal or even a theory; advocates for intersex people stated that this theory was wrong, confusing and unhelpful to the interests of intersex people. In a later paper ("The Five Sexes, Revisited"), she has acknowledged these objections.
"Not surprisingly, it is extremely difficult to estimate the frequency of intersexuality, much less the frequency of each of the three additional sexes: it is not the sort of information one volunteers on a job application. The psychologist John Money of Johns Hopkins University, a specialist in the study of congenital sexual-organ defects, suggests intersexuals may constitute as many as 4 percent of births. As I point out to my students at Brown University, in a student body of about 6,000 that fraction, if correct, implies there may be as many as 240 intersexuals on campus - surely enough to form a minority caucus of some kind."
This section of the essay is not tongue in cheek. She clearly states she's teaching this idea.
This was John Money's response
"To the best of my knowledge there is no publication attributable to me in which I suggest, as Ms. Fausto-Sterling puts it, intersexuals may constitute as many as 4 percent of births. Moreover, it is epidemiologically reckless to conjecture that on the campus of Brown University there are 240 students with a birth defect of the sex organs that would justify their being diagnosed as intersexuals, that is, hermaphrodites"
[1] https://pdfs.semanticscholar.org/21a4/4d10b40354a974c8d1d3a9...
You have referenced the 2000 essay, "The Five Sexes, Revisited"
No on claimed it was a scientific investigation, I quoted the full text of the issue I was discussing in a previous comment.
(Yes, Keller is a physicist, not a biologist. Those trying to belittle or dismiss what women's studies has accomplished will probably use that to disqualify her contribution...)