These estimates are off by more than a factor of 10.
A true, conservative estimate is that more than 1 in 150 people are born with intersex bodies. In this post, I'm going to explain why the true commonplace of intersexuality is so widely underestimated. And yes, I'll justify my 1 in 150 estimate by the end.
There are two main reasons reasons why nobody can give you an exact figure for how many people are intersex. The first is that there is nobody gathering this data. And the second is that in trying to come up with an estimate, people rely on medical diagnostic categories that purposefully deny that many people with sexually-intermediate bodies are “really intersex.”
Let's begin with the matter of gathering data on who is intersex. A central problem we run into is that nobody is funding a cross-condition population study of sex variance. This is the case in part, ironically, because being intersex is perceived as a rare thing. In addition, being intersex is framed as a “treatable medical condition.” Thus, there's little sense of intersexuality being an urgent matter to prompt government or private entities to fund a large exploratory study. But even if a large study of all physical sex variance were to be funded, you'd run into problems with people not wanting to disclose their bodily statuses. Some intersex conditions are obvious at birth when children have visible genital variance. But these children are immediately assigned a dyadic sex, male or female, on their birth certificates. The children and their parents are told by doctors that they must conceal the childrens' “defect.” With both the medical profession and our society at large treating intersex status as something freakish and shameful, people who are born visibly intersex are usually extremely closeted about their status, and don't want to be studied, outed, exposed. They are unlikely to want to take part in studies.
Furthermore, many people are intersex without it being genitally obvious. Some people are chromosomally sex-variant: they have a genotype such as XYY or XXY that is not associated with a significant disability, or they are XY women or XX men. Such people may never find out that they are intersex—after all, have you ever had your sex chromosomes screened? Other people have variant internal reproductive organs. I, for example, had an ovotestis, a gonad intermediate between an ovary and a testis. I'd been told I had a supernumerary ovary after pelvic exploratory surgery, and it was only years later, after I'd had my internal reproductive organs removed, that a pathologist informed me it was actually an ovotestis. What this illustrates is that in order to do a mass study of the frequency of intersexuality, you can't just rely on interviews and on existing medical records. One would have to do extensive medical testing, including biopsies, of all the people studied, which would be very invasive.
Even if you were somehow able to get a large, representative, random subpopulation of people to agree to be genitally examined, hormone-screened, genotyped, CAT-scanned, and to have their gonads biopsied, the frequency of intersexuality would be drastically underestimated. And that is because of the second problem I mentioned: that of medical diagnostic categories.
Let's think commonsensically and rationally for a moment.
What does it mean to be intersex? Logically, it means that a person has a body that is intermediate between the idealized male and female poles of the sex spectrum. All of us start out in the womb with an intersex form, having a phalloclitoris, labioscrotum, and ovotestes (you can read more about this in this post). It's expected that these should differentiate as we develop, but in fact one or more elements of the sexual anatomy may stay fully intermediate, or may differentiate only partially. Any person who has a body that is not fully sex-differentiated is, logically speaking, intersex.
But medical diagnostic categories are not logical, despite our ideology that they should be so. The majority of individuals born with intermediate sexual anatomies are not given an intersex diagnosis. I believe that what underlies this is gender ideology. And that gender ideology is this: masculinity is fragile, especially when it comes to what a man has in his pants. To live as a man with an inadequate penis is seen as intolerable. To have one's status as a “real man” challenged is viewed as psychologically crushing. Thus, doctors feel, if they were to categorize someone as intersex and then assign them male, they would be acting cruelly. Women, on the other hand, are perceived as more gender-flexible. After all, it's reasoned, a woman isn't shamed by wearing pants or taking on a power career. Viewing female-assigned people as more comfortable with androgyny and as better at dealing with emotional challenges, doctors believe that if they diagnose someone as intersex, they should assign them to the female category.
Thus, under current the current regime of medical diagnosis and treatment, the large majority of people labeled by doctors as intersex are assigned female at birth. People who are diagnosed under the rubric of “female pseudohermaphrodites" (a ridiculous term devised in the 19th century for intersex people with ovaries and intermediate genitalia or a phallus) are assigned female, and their phalli are surgically removed. People who are diagnosed under the rubric of “male pseudohermaphrodites,” with internal testes and genitals that are intermediate or vulvic, are also assigned female, and their testes removed.
Under this regime, most people—including academic gender scholars, doctors, and even a substantial number of intersex activists—believe that “almost all intersex people are assigned female at birth.”
You'll find this statement oft-repeated, but it's not true. At least as many babies with sex-variant bodies are assigned male at birth. It's just that the majority of them are not diagnosed as “true hermaphrodites” or “pseudohermaphrodites.” Many, for example, are characterized as “real boys” with a "urethral malformation." The diagnosis they receive is “hypospadias.”
Hypospadias occurs when a person develops testes, but the phalloclitoris is intermediate in form. People with hypospadias can fall anywhere on the sex spectrum from having fully intermediate genital configurations to having forms little different from what is considered typically male. (You can find illustrations midway down the page here.) In cases of what is termed “first degree hypospadias,” the person has close to idealized male anatomy, but the urethra opens on the underside of the penile glans. As the degree of hypospadias increases, the opening is lower on the phallic shaft, and is larger and more vulvic in form. In perineal hypospadias, there is a substantial vagina, the phalloclitoris is intermediate in structure, and the testes may be internal. And the bodily variance is not limited to the external genitalia. Hypospadias is associated with an enlarged prostatic utricle, which may vary from a slight enlargement with low degree hypospadias, to a full-sized uterus in high degree hypospadias.
Rationally speaking, people with hypospadias are intersex. They share with other intersex people not only sex-variant anatomy, but the common experience of imposed genital-normalizing surgery in childhood, and the unwanted consequences of loss of sensation, infections, scarring and fistulae. And while individuals with mild hypospadias appear to be almost as likely to identify with their assigned sex as individuals with typical phalli, those with advanced degrees of hypospadias are much more likely to suffer from gender dysphoria with their male assignment. For medicine not to acknowledge that hypospadias is an intersex condition seems not only nonsensical, but often cruel. It may be true that people born with hypospadias who identify as male don't want to be publicly labeled intersex, just as male-identified people don't often buy T-shirts that say “Ask me about my erectile dysfunction!” or “Just call me Cocktail Wiener.” But our cultural obsession with male-classified people having large erections and unquestionable male status should not dictate medical diagnostic categories.
Now, here comes the kicker.
According to the CDC, hypospadias occurs in the U.S. in one in 125 children labeled as “boys,” or 1 in 250 births. In other words, if we looked only at this one condition, the minimum rate of intersexuality is 1 in 250.
There are other intersex conditions that are not diagnosed as such, though they are medically treated in the same way as other intersex conditions. Consider “clitoromegaly” and “micropenis,” the diagnostic terms for people with a clitorophallus of intermediate size. A child born with clitoromegaly is assigned to the female category, and today in the U.S. is given “clitoral reduction” surgery in the same way that a child diagnosed as a “female pseudohermaphrodite” is altered. Children born with micropenis in the U.S. are classified as boys, and must often endure surgical and hormonal interventions (sometimes even what is officially termed infant sex reassignment to female status). Yet individuals with clitoromegaly and micropenis are often not diagnosed as “offically intersex.”
So let us just look at individuals born with genitally intermediate bodies who are assigned male at birth. Micropenis occurs in 0.6% of male-classified people, or 0.3% of the population. Hypospadias occurs in 0.8% of male-classified people, or 0.4% of the population. Just looking at these two conditions, 0.7% of the population is born sex-variant. In other words, translating to odds, 1 in 142 people has either hypospadias or micropenis. That's more than 1 in 150.
We now see what happens when we employ the rational rule of classifying anyone who is genitally, gonadally or chromosomally intermediate as intersex. We logically include people with hypospadias and micropenis in the intersex category instead of excluding all conditions in which infants are assigned male. Now, for the sake of argument, let's just accept at face value the assertion that all other intersex statuses are so rare that the chances of having any other variation in gonads, genitals or chromosomes is 1 in 2500. I consider this extremely unlikely, but we'll just go with it. In fact, for the sake of our argument let's accept the ridiculous assertion a medical student once made to me: that there have only been 7 “real hermaphrodites” ever encountered in all of recorded medical history. By this logic, the chance of having any other intersex variation is 1 in a billion, or to simplify, basically 0. But we're still left with a minimum of 1 in 142 individuals having an intersex body.
That puts being intersex about on par with the likelihood of having green eyes.
Personally, I believe the rate is much higher. I do think it's unlikely we'll ever come up with an unquestionable exact number of intersex people, even if we get study funding and widespread permission from study populations, and even if medical diagnostic categories cease to be so irrational. Sex is a spectrum, and any way we slice up a spectrum is arbitrary and open to debate. (I remember my mother and grandmother perpetually arguing over whether the color turquoise was “really blue” or “really green,” and one could have similar endless arguments over the point at which an intermediate phalloclitoris is sufficently large-headed to “count” as a penis or sufficiently small-headed to “count” as a clitoris.) But at a very conservative minimum, more than 1 in 150 people have sexually intermediate bodies.
So the next time someone tells you that intersexuality is extremely rare, tell them otherwise. The next time you see a book about pregnancy that talks about uncommon complications and rare infant differences but never mentions how often babies are born intersex, raise a fuss. If you hear the old saw that “all intersex people are assigned female at birth,” clear up that misunderstanding. Be aware and help make others aware that the problems facing intersex people are not sad rarities, but burdens faced by many (over 2 million in the U.S. alone). And if you yourself are intersex and living a life in closeted shame, I urge you to stop believing you must live your life isolated and alone. You have a lot of siblings out there.