TWO PERCENT?

Whenever I'm involved in conversations about intersex- or trans-related issues someone conflates trans with intersex and notes that one or both, or all of the above, are "as common as red hair." I'm told that, like the incidence of red hair, those who are intersex make up "roughly 1-2% of the population." And if you go looking, this assertion is everywhere. It's forwarded by everyone from international human rights organizations (from the UN to Amnesty International and on) down to local LGBTQ+ groups, from late-career scientists to fledgling political activists and everywhere in between.

Having the experience I did with grad school and my thesis (discovering that a set of common assertions found across many disciplines is undeniably false) and also having investigated similar statistical claims to the above (such as that "people don't lie [about abuse]" and that "those that do are an insignificant few" – only to learn that around 3% of "victims" are nothing of the sort and that, moreover, this "tiny fraction" is an astonishingly large number), I wanted to learn more about the origin and basis for this statistical fact about the incidence of intersex conditions.

The first thing to note is that this small single digit percentage is framed as being very large, so at least we are making sense. The reason for this accurate portrayal of the magnitude of this figure is because it is commonly forwarded to uplift and normalize a marginalized minority. These are, after all, folks who are commonly and undeniably the victims of various 'corrective' surgeries that are, like circumcision, typically both unnecessary and non-consensual. So representing a substantial figure as such feels like a perfectly good thing to do and the kind of world I want to live in. Good start.

But how did we arrive at this stat, one that everyone everywhere seems to be quoting? As far as I can tell, Brown University professor, Dr. Anne Fausto-Sterling, first came up with this number and published it in their 2000 book Sexing The Body: Gender Politics And The Construction Of Sexuality. Shortly after, and with collaborators, an elaboration was published in the American Journal of Human Biology, in a work titled How Sexually Dimorphic Are We? There Fausto-Sterling et al. set out to disprove "the belief that Homo sapiens is absolutely dimorphic."

The authors do so first by defining intersex as "an individual who deviates from the platonic ideal of physical dimorphism at the chromosomal, genital, gonadal, or hormonal levels." From there they define their "ideal male" very precisely as: a person one with XY chromosomes, functional testes located in the scrotal sac, a penis 2.5-4.5cm at birth, and a completely enclosed urethra that opens at the tip. This person must also have testes that produce mullerian inhibiting factor as well as testosterone and dihydrotestosterone. Juvenile testicular activity must also result in typical masculinizing puberty. The author's definition of female is similarly narrow. An "ideal female," they tell us, has: two X chromosomes, intact oviducts attached to a functional uterus, cervix, and vaginal canal. This ideal must also have labia minora and majora present, a clitoris that ranges between 0.20-0.85cm in length at birth, as well as functional ovaries that result in normal feminizing puberty.

And then, to get us to this now-famous number, the authors take these definitions and survey half a century of medical literature to look for how often humans stray, by any measure, from what they assert to be ideal forms. Using the above criteria lands roughly 1.7% of individuals outside their stated ideal and within the authors' definition of intersex. The paper notes, however, that as much as 2.27% of the population could fit into this category if only this criteria could be broadened further.

So, what of this set of definitions? It seems worth asking if this profoundly narrow definition these authors invent is accepted by anyone or even considered coherent? Without looking we know that Fausto-Sterling and team are eager to equate any difference of any kind in sexual development with intersex. That seems to clearly rewrite biology and establish a novel and clinically-irrelevant definition that is carefully crafted to erase one that happens to make sense in clinical terms. We know at the outset that all intersex conditions, by definition, express differences in sexual development; however, we also know that not all difference is sexual development are intersex. All of this is a real problem for these co-authors and the originator of this stat we're considering. In a 2002 paper titled How Common is Intersex? A Response to Anne Fausto-Sterling, Dr. Leonard Sax makes this perfectly clear. This physician and psychologist highlights the fatal flaw in this 1.7% figure and the definitional elongation (read: error) that got us to it.

Eager to inflate the category, the incidence rate includes conditions that cannot possibly be considered intersex. As a matter of fact, conditions making up vast majority of Dr. Fausto-Sterling’s figure do not result in any sexual ambiguity of any kind. So they would redefine the term 'intersex' such that its prefix 'inter' (meaning ‘between’), and thus the very word itself, is effectively irrelevant. To explain and get specific, Dr. Sax reminds us of Turner and Klinefelter syndromes as well as late-onset adrenal hyperplasia. Sax offers that "[i]f the term intersex is to retain any meaning, the term should be restricted to those conditions in which chromosomal sex is inconsistent with phenotypic sex, or in which the phenotype is not classifiable as either male or female." That would be coherent.

So how big is this group of conditions of non-ambiguous sexual development that Fausto-Sterling and team would commandeer to arrive at their 1.7% rate? Well, as Dr. Sax notes, almost all of this 1.7% includes a single condition: late-onset adrenal hyperplasia. But folks with this condition very rarely have ambiguous sex at all; instead, they have perfectly typical genitalia at birth, genitalia that also aligns perfectly with their sex chromosomes. As such, re-labelling late-onset adrenal hyperplasia as intersex is a the radical rewriting of biology and language. It looks to me nothing like the clarification or rectification of a broken definition. And it doesn't feel like raising awareness or extending compassion to people being victimised. And then it is also worth acknowledging that, by this one example alone, Fausto-Sterling's number deflates by almost 90%, to something closer to 0.2%. (This figure, interestingly, also happens to be the same rate cited in Fausto-Sterling et al. for fifty years of data on people receiving 'corrective' genital surgery.)

Dr. Sax also notes Turner and Klinefelter syndromes. These are chromosomal deviations from what we understand to be the more typical XX or XY configuration. That said, neither of these conditions results in ambiguous genitalia or distinct sexes – and therefore aren't, in any clinical sense, considered intersex. And if you go look at vaginal agenesis, the next most common condition on Fausto-Sterling’s list, this too has never been considered an intersex condition. Girls with this condition are unambiguously female: they possess typical chromosomes and ovaries, and are able to become pregnant and birth their own children.

So, by sorting out the confusion above, Dr. Sax finds a coherent clinical definition to yield an incidence of intersex orders of magnitude smaller than that argued by Fausto-Sterling and crew. When developmental sexual differences lacking any ambiguity are removed from Fausto-Sterling’s overly-broad category, and intersex conditions are defined as those in which "the phenotype is not classifiable as male or female, or 'chromosomal sex is inconsistent with phenotypic sex,'" as Sax explains, "the real prevalence of intersex is seen to be about 0.018%..." Then, just to look at what seems like a more reasonable number, we have intersex being far rarer than something as common as having red hair and closer to the incidence of being born left-handed, blue-eyed redhead.

From there, if only to me, what is framed as an illumination and a kindness, a broadening of the category to be more inclusive, feels more like the manipulation of an already victimized minority. While a century of human rights efforts worked to establish a global precedent that human dignity and legal rights are intrinsic to the individual and not based on group membership, Dr. Fausto-Sterling et al. appear to make a tacit argument against such global appeal for equality. And how have they chosen to get there? By aggressively contorting language, statistics, biology, and just about all the rest of reality.

Apparently it needs stating again. When you have to distort reality – by fabricating statistics, redefining words to mean their opposite or to obliterate meaning altogether, or reverse-engineering facts – all in an effort to achieve justice – you are not, in fact, eliminating injustice but only shifting the locus and then refusing to see what you've done. And that, my friend, is truly messed up.