If you spend any time online discussing matters of sex or gender, you’ll inevitably encounter the claims that “sex isn’t binary”, “sex is a spectrum”, or the even more impressive sounding claim “sex is bimodal”. While from a Queer Theory perspective, a movement focused on deconstructing and abolishing normativity and categorization, I can understand why someone wants to deny one of the most fundamental biological categorizations (sex), it is as of yet unclear to me why anyone else would want to participate in this ideological nonsense. The binary of sex has no impact whatsoever on the validity of gender dysphoria after all.
Sex is binary
Almost all complex life forms reproduce through the fusion of two differently sized reproductive cells called gametes. This process is called anisogamy, and the two reproductive roles in that process are called sexes. That’s why the two sexes are defined by gametes. Since there are exactly two sexes, male and female, and a binary is a set consisting of exactly two values, sex is, by definition, binary. For those interested in how those two sexes developed, I can recommend the paper “Gamete competition, gamete limitation, and the evolution of the two sexes“.
Is sex a spectrum?
A spectrum is a range or ordered set of values. Since there are only two values for sex, male and female, and since there is no order to those sexes (though some religious conservatives seem to value the male sex more), sex can, by definition, not be a spectrum. Some sex characteristics, such as height, are on a spectrum, but to claim that sex is on a spectrum because some sex characteristics are on a spectrum is a category error.
Is sex bimodal?
The only things that can be bimodal are a set and a distribution. As such, sex can, by definition, not be bimodal. A bimodal distribution is a distribution with exactly two modes, two values with the highest frequency (or local maximums on a graph). This requires more than two values, because if both values have the same frequency the distribution is uniform. Some sex characteristics may have a bimodal distribution, but that does not mean that sex has a bimodal distribution. Contrary to popular belief, height is not one of those sex characteristics.
What about intersex?
Intersex is not a sex. Intersex is an umbrella term for a subset of DSD (disorders or differences of sex development); congenital medical conditions that affect male and female sex development. As such, intersex isn’t something you are, an intersex condition is something you have. People with an intersex condition or other DSD are just as male or female as everyone else, but their disorder of sex development may cause sex characteristics that are atypical for someone’s sex. Of course this does not change their sex. A tall woman is just as female as a small woman. A man that develops breast tissue due to Klinefelter syndrome is just as male as any other man.
Some DSD may cause more confusion though. Caster Semenya, the famous South African 800m runner, for example has 5-ARD, a disorder of male sex development that prevents proper development of the penis and scrotum. In some cases, like Caster’s, this causes children to be incorrectly observed as female at birth, while they are in fact members of the male sex. In general, such cases become apparent during puberty.
Do 1.7% of people have an intersex condition?
This is a claim by Anne Fausto-Sterling, which is still far too often used by large international organizations that should know better. Biologists Leonard Sax and Colin Wright have explained that for the term intersex to actually have medical relevance, it should be limited to those DSD that actually show ambiguity at birth. Looking at the 1.7% claim, it is clear that a lot of conditions have been included for ideological purposes to inflate the number (some people these days even include PCOS to inflate the number even further to 4%).
1.5% of that 1.7% (so 88%) consists of people with Late-Onset (Congenital) Adrenal Hyperplasia (LOAH or LOCAH), an autosomal recessive disorder that usually doesn’t set in until late childhood or early adulthood. To include that in the term “intersex” is highly questionable at best. Of the remaining 0.2%, about half (0.1%) suffer from Klinefelter syndrome, a disorder of male sex development due to additional X chromosomes, the most common associated karyotype being 47,XXY (or XXY for short). These people are unambiguously male. Of the remaining 0.1%, about 40% (so 0.04%) suffer from Turner syndrome, a disorder of female sex development due to a missing X chromosome (45,X). These people are unambiguously female. In the end, less than 0.018% of people suffer from an actual intersex condition, a factor 100 lower than Anne Fausto-Sterling’s claim, and as explained above: even those people are still members of the male or female sex.
XX vs XY
Unfortunately, too many people these days try to simplify the discussion by claiming that XX = female and XY = male, or “if you have a Y, you’re a guy”, and everything else is an anomaly. While variations in karyotype are indeed not very common (< 0.2%), karyotypes are not sexes. Sex development in humans is determined by genes rather than the chromosomes that carry them, most notably the SRY gene. As such, rare male sex development in people with a 46,XX karyotype (De La Chapelle syndrome) exists as does (even fertile) female sex development in people with a 47,XXY karyotype, primarily due to translocation of the SRY gene.
Man vs woman
Another often heard claim is “male and female are sexes, but man and woman are gender identities”. This claim is incorrect. In biology, male and female are cross-species terms for the two sexes, but species specific terms also exist, such as bull/cow (bos taurus), rooster/hen (chicken), and man/woman (human). That’s why in the dictionaries, man is defined as adult male human (an adult member of the male sex of the human species) and woman is defined as adult female human (an adult member of the female sex of the human species).
Whether these terms should be considered homonyms and also defined as gender identities is for the claimants to prove. I have as of yet never received a non-circular definition of any of these gender identities, nor a set of objective criteria that could be used to determine one’s own gender identity. As such, I remain skeptical.
Nathaniel Hart
