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The biological ironies of transgender debates

Transgender issues have made significant headlines in the United States. Not long ago, North Carolina struggled to repeal a 2016 law that required people to use only public restrooms that matched the sex on their birth certificate, not their lived gender identity. Only weeks earlier, the US Supreme Court declined to hear a case from a Virginia student on the same issue. Then, in mid-April, over eight million viewers of the “Survivor” TV series watched as one competitor tried to malign a fellow contestant by exposing him as transgender.

At the same time, however, common cultural assumptions surrounding “basic” conceptions of sex and gender are replete with ironies. They assume that male and female should be clear, discrete categories; that assigning sex unambiguously is an appropriate baseline; and that anatomies, physiologies, and behaviors naturally align in a uniform and dichotomous fashion. Not so, biologically speaking. How, indeed, do we define male and female scientifically? Regardless of one’s definition, exceptions can be found. Sex is not either-or. Accordingly, a binary framework for interpreting gender seems ill-informed.

For example, consider an individual who due to their genetic profile does not generate the enzyme 5-alpha-reductase (as portrayed in Jeffrey Eugenides’ Pulitzer Prize-winning novel Middlesex). Such a person, based on outward appearances, will be labeled female at birth. At puberty, however, hormone levels change, the penis grows, and the voice deepens. Male gonads, one finds, had been there all along. But the development of the other traits had been dramatically displaced in time. Cases in one village in the Dominican Republic are so common that they have a special name: guevedoces, or sometimes machihembras. What does “sex assigned at birth” mean in a case like this, when so much changes?

“Amphiprion ocellaris (Clown anemonefish)” by Nick Hobgood. CC BY-SA 3.0 via Wikimedia Commons.

Nor is sex necessarily static or fixed. Many tropical fish change sexes during their lifetime, sometimes in a matter of hours. In clown fish, when females die, males can become females—a provocative detail not depicted in the popular animated film, Finding Nemo.

In other species, both sexes exist simultaneously. Snails, earthworms, barnacles, and many deep sea fishes are hermaphrodites, having both types of gonads, and play two reproductive roles. Sex is not exclusively either-or.

Traits associated with the sexes are not consistent either. Not all humans with testes develop extensive facial hair or muscle mass. Nor do all those with ovaries develop large breasts or exhibit menses. Mosaics of all sorts can be found—all produced by natural causes. In some mammals, such hybrids are the norm—in spotted hyenas, kangaroo rats, bush babies, and Old World moles. Thus, one cannot universally correlate any set of traits exclusively with one type of gonad. These features, so often used to delimit the sexes, hardly assort uniformly, and therefore cannot definitively distinguish male and female.

Many people imagine that biological science can establish sex unambiguously. In a common perception, the chromosomal makeup of human females is XX, and males XY. Yet in some individuals, the genes that activate hormones related to differences in male fetal development have been translocated to an X-chromosome. The developmental male is XX. Other chromosomal combinations, such as XO and XXY, are well documented and have their own distinctive body biologies. Relying on genetics and chromosomes does not resolve all cases.

Spotted Hyena from Etosha National Park, Namibia by Yathin S Krishnappa. CC BY-SA 3.0 via Wikimedia Commons.

For similar reasons, even behaviors cannot delineate male and female. In one fascinating pair of experiments, the genes of some fruit flies were manipulated, generating ostensibly female flies that exhibited typically male mating behavior and males that did not. In seahorses and spotted sandpipers (among other species), males are the primary protectors of offspring. Does that make them less “male,” or transgendered as “maternal”?

As indicated by these many examples, organisms that do not follow conventional conceptions of male and female are biologically widespread. Nor are human cases rare. In the United States, the transgender label includes some 1.4 million individuals, or more than one in every 200. One cannot easily dismiss them as mere “exceptions.” They arise through nature. Yet ironically some people view them as “unnatural.”

Ultimately, there is no biological foundation to male and female as discrete, pure categories. Accordingly, such labels on birth certificates have limited scientific meaning. The very conceptions of gender and transgender, especially as related to sex, begin to dissolve.

Issues about personal identity surely matter. Yet public discourse might benefit from reflecting on why we adopt the categories of male and female and imbue them with such significance. Why do so many people consider them “natural”? And, finally, what is at stake—politically, ideologically, and culturally—in trying to preserve sex and gender as unambiguous dualities, when the biology does not support them? Perhaps we might gain more insight into why the notion of transgender individuals seems to elicit such deep emotions and controversy.

Featured image credit: Borghese Hermaphroditus Louvre Ma231 n4 by Marie-Lan Nguyen. Public Domain via Wikimedia Commons

Recent Comments

  1. Kenny

    Gender has been viewed as a binary because historically humans have attached great significance to reproduction and family structures that are centered around the rearing of children. St. Augustine in his _City of God_ essentially admits that all human sexual acts would be equal if it were not for what he viewed as the privileged one: the generative act of conception. And I believe that humans are not the only life forms that believe that reproduction is a very important life function (if not the most important one). I am not a biologist, but I assume that the cases of hermaphroditism and ambiguous sexuality in other species do not inhibit reproduction. If anything, I could imagine that they are strategies that maximize reproductive potential. After all, wouldn’t those behaviors and physical features be chosen by natural selection simply because they were effective at propitiating those genes to the next generation?

  2. Jules Levin

    Bathroom use is a red herring for both sides. Bathrooms are the equivalent of trash dumps divided between recycle and garbage. The only determiner of use should be the plumbing, not the birth certificate and not one’s “feelings”. If you dispose standing up, use the stand-up washroom; if you sit down, use the sit-down washroom. Period.

  3. Sergio Salazar

    I have some issues with this article. First, I agree there is a real general discrimination against transgender people and it is undisputable this is wrong, especially because we know there is a very strong genetic component in this cases -I will not argue against this points, because in this, I agree with the author. Practically nothing in biology (and medicine, as really a very specialized branch of biology) is black and white; as I like to say, biology/medicine is not mathematics. What this means is that although when you have certain conditions, most, but not all subjects present some biological feature, so it is usual to find exceptions to almost every rule. This in itself is not necessarily an argument against the rule. In fact, that is why people usually say that the exception proves the rule, it is not ironic nor contradictory to state this, the phrase just intents to direct attention to the fact that precisely because the vast majority of cases behave a certain way it is obvious when a rare case does not, proving it different than most. The case of sex is not different. Sex is indeed determined by chromosomes, X and Y, although to be more specific, it is determined by genes that are usually found in each of this chromosomes. That is why, when some individual possess some of the genes involved in sex determination (or normal sexual development) normally in the Y chromosome but now placed on the X chromosome, this individual may develop male characteristics and even behavior. Yes, our genes also generically determine behavior, and there is a whole branch of genetics [a very serious scientific enterprise] devoted to that: behavioral genetics). A lot of factors will play a part, developmental accidents, environmental exposures, the other version of the genes that interact with them (other relevant or connected alleles and pleiotropic effects), among others. The phenomenon -without a doubt- is complex. Now, this is just sex, what people now refer as gender is even more complex than that, but without a doubt is still rooted in biology. Actually, there is a huge overlap, meaning most males and females are straight, and accommodating to reasonable variation, since biology is all about statistics, mostly showing bell curves, when most people will be gravitating around the middle with less individuals in both tails. I will even say that gender (or sexual preference) is chaotic, meaning it is so complex, it is impossible to make an unequivocal prediction of it starting with data from a whole genome sequencing, even when knowing a lot about genetics, molecular biology, cellular biology, biochemistry, endocrinology, and other relevant fields. All these concepts are relevant, not so the fact that clown fish can change sex (“Nor is sex necessarily static or fixed” –in humans?) or that hermaphrodites exist in nature in other species. Now, the fact that “Traits associated with the sexes are not consistent either” is just the manifestation that sexual characteristics admit variation, a whole gamut of it, and should surprise no one as I have stated. Now, that plus the fact that, again, other species are able to produce mosaics, cannot sustain the conclusion that therefore you “cannot definitively distinguish male and female” (by the way, our human females are all mosaics, because they mostly use only one X chromosome and silence the other one, some cells use the paternal one and some the maternal one). It is tiresome to hear over and over the sloppy reasoning that because there exists exceptions, then the rule has to be false. How many XX humans are male? How many XY humans are female? From here the author turns to behavior and bases his conclusions on flies (because there is no better evidence?).
    This assertion is incredibly strong, and, of course, incredibly ignorant too -“Ultimately, there is no biological foundation to male and female as discrete, pure categories”, of course, there is! Whenever you want to be pure in biology, you will find yourself bending over backwards; that is simply not the nature of biology, again, biology or medicine are not mathematics. Variation is at the core of biology, because it is at the core of evolution. We certainly need stability (you cannot be too different that you are unable to reproduce, your lineage will end with you then), but some variation is also indispensable to try different ways to handle with the world; some will be more likely to succeed than others.
    I agree that “Issues about personal identity surely matter”, but the argument sustaining this assertion should not be based in false conceptions, misapprehensions, or confounding notions. Science can state the facts and the reasoning is straightforward. What is more important to know is that sexual preference (or gender identity for that matter) is a phenomenon rooted in biology, nobody chose it for himself, you were born that way and in that sense it should be treated like nationality or height.
    This is just a comment that got a little long, still much more elaborated arguments can be deployed, but I think I have said enough.

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