The role that the much misunderstood and mythologised hormone testosterone plays in the development of males is causing ructions going all the way to the Olympics. By Andrew Anthony.
When Laurel Hubbard was selected for the New Zealand Olympic female weightlifting team, it ignited a controversy that travelled around the world. In becoming the first transgender woman to represent her country (as a woman) at the Olympics, Hubbard landed in the centre of a debate that has been growing ever more impassioned both in sport and society at large.
Somewhere within the complex web of arguments and counterarguments lies the disputed role of an androgen hormone that is often seen as the very essence of masculinity: testosterone. Many supporters of Hubbard maintain that she has such low levels of testosterone, as a result of hormone treatment, that she does not enjoy any advantage over natal female competitors. And some go so far as to suggest that there is little evidence that testosterone confers an advantage anyway.
But opponents of the decision to send her to Japan maintain that the high level of testosterone Hubbard experienced in puberty as a male created a musculature and density of bone structure that do indeed provide an advantage over natal female competitors.
Alongside the scientific claims and counterclaims are a range of cultural assumptions and beliefs that inform our ideas about testosterone and, some suggest, affect the questions we pose and answers we seek.
For most of the past century, testosterone’s role in popular culture was so reductive as to be verging on the comic. Often subject to crass stereotyping and crude extrapolations, it worked as the all-purpose shorthand for macho and aggressive behaviour. Underlying this common caricature, however, was a conception that many people, in particular a number of feminist thinkers, found disturbing.
If aggression was directly linked to testosterone levels and testosterone levels were largely natural, did this mean that men weren't responsible for their aggression? Could they be portrayed – not least by themselves – as the innocent victims of their hormones? From wolf whistling and street brawling to domestic violence, rape and murder, all manner of "toxic masculinity" may therefore be explained – and perhaps even justified – by the science of endocrinology. At least, that was the concern. As a result, a backlash grew against the notion that male behaviour was shaped by hormones, most specifically testosterone.
“Distortion” of science
A couple of years ago, cultural anthropologist Katrina Karkazis and women's and gender studies professor Rebecca Jordan-Young published a book called Testosterone: An unauthorised biography. In it, the pair take aim at the dominant narrative that testosterone is "about libido, aggression, focus [and] facility with science and math". When I spoke to her in 2019, Karkazis told me there was minimal evidence that testosterone is linked to aggression. As she put it: "It's an artefact of the ideology of testosterone that we continue to believe that it drives aggression, because aggression has been framed as a masculine behaviour and testosterone has been framed as a masculine hormone."
This argument is one that is heard a lot nowadays, and it also extends to the relationship between strength and testosterone, which is obviously relevant to Hubbard's position in the weightlifting team.
Although Karkazis and Jordan-Young’s book predated the Hubbard controversy, it nonetheless articulated the argument employed to defend her inclusion in the female Olympic team. The joint authors argued that one renowned endocrinology study – by Shalender Bhasin – overstated the effect of testosterone on building muscle. Instead, Karkazis and Jordan-Young attributed muscle growth to exercise, stating that “T alone didn’t do much”. (T is a common abbreviation for testosterone.)
Yet as Carole Hooven, a human evolutionary biologist at Harvard University, explains in her new book, Testosterone: The story of the hormone that dominates and divides us, Karkazis and Jordan-Young misrepresented Bhasin’s study. In fact, the results of the study showed that testosterone significantly increased muscle and strength – even without exercise.
Hooven is horrified by what she calls the "distortion" of good science, which is then repeated and further distorted in the media before an utterly warped version of reality filters into the general consciousness.
"Testosterone builds muscle, men have more of it and it gives them a strong advantage over women in sports," she states in admirably clarifying prose.
As she told me, "by the same token, there is nothing about the actions of T in our bodies, our evolved natures or, in fact, any aspect of our biology that implies that we just have to live with current levels of sexual assault, harassment, discrimination or coercion. Quite the contrary; the more we understand about how our inherited biology interacts with our environment, the better equipped we will be to create a safer, more just society."
We are, as she said, “big-brained apes that are capable of self-reflection and self-restraint”. In any event, she says, whether or not biology is used as a weapon of the patriarchy is irrelevant to the truth of scientific hypothesis. “And in the case of testosterone,” she writes, “it is hard to avoid the conclusion that these irrelevancies are motivating a lot of the critics.”
Blank-slate hypothesis
Why does this argument matter? Isn't it just a spat between endocrinology and anthropology about a scientific paper that hardly anyone will bother to read? That's certainly one way of looking at it. But it's also true to say that this issue goes to the heart of who we are as men and women, and that in turn raises the age-old question of what most influences us: nature or nurture?
While acknowledging that testosterone is an important hormone – for both men and women – Karkazis and Jordan-Young prefer to see "masculine" behaviour and even physiology as culturally produced. Essentially, this line of thinking says that boys play with guns and fight because that's what they're taught to do, rather than because they're biologically compelled to act that way. And girls tend towards less aggressive forms of play because, again, that's what they've been taught to do.
The problem with this analysis, says Hooven, is that it's based on an idealistic vision of the world, not on empirical evidence. In this vision, everyone is born with a sort of blank slate, more or less, and then society sets about dividing and defining and limiting the options open to children by herding them into heavily gendered groups of boy and girl, blue and pink, aggressor and peacemaker.
Why are so many people so drawn to favouring cultural over biological explanations for behaviour? As Hooven says, “People’s fear of biological explanations for behaviour seems to stem from a few different sources. First, there’s a long history of people using science as a way to try to justify discrimination of all kinds. So, it’s reasonable to be sceptical of claims that things like higher rates of male aggression have a basis in our biology.
"And second, people mistakenly believe that if something is 'natural', then it is both immutable and justified. But it's natural for little kids to throw their food. They are far more likely to engage in this behaviour than you and I are.
“Whether they actually engage in this behaviour, however, is highly dependent on the past consequences for such behaviour, what they had for breakfast, the cultural norms where they were raised, etc. The environment matters. And such a behaviour is not good just because it is natural Understanding what drives the behaviour can help parents and caregivers figure out how to set up the environment to make it less likely.”
Although we can all think of situations in which this picture resembles societal interventionism, most parents will testify that their children began behaving in gendered ways before they were exposed to any outside influence. To which the nurture camp would say that parents themselves impose these ideas about "boys" and "girls", even if they don't mean to.
"Of course, parents and peers do try to mould children into people who fit into various social roles – particularly gender roles," Hooven says. "But the evidence simply does not show that these influences work. Instead, it shows that kids mostly do what they want and that their feminine or masculine natures will emerge despite any efforts to condition them."
Almost everyone agrees that regardless of whether masculinity is a biological evolutionary development or a cultural construct, there are many exceptions to the rule. Plenty of girls are "tomboys" and plenty of boys are passive or highly sensitive. But the exception to the rule does not mean the exception is the rule.
Nearly all killers and rapists are men, and in this there are important links to many other mammals. A large body of research has been done on the effect of testosterone on various mammals, none of which are known to impose blue-pink types of demarcation, although they do show strongly divergent behaviours between the sexes. Perhaps the most notable study has been on rats.
Says Hooven, "The effects of testosterone on behaviour start well before puberty – in fact, they start in utero, coordinating the development of male reproductive structures, like the penis, with the neural foundations to be motivated to use it. And in many mammals, being able to use it requires physical aggression, in the competition for mates. We can see examples of these early effects quite clearly in rats, and there are strong parallels to the effects of early T on behaviour in humans."
Insights from disorders
Young male rats are more aggressive in their play than young females (as is the case with humans). More aggressive rats are better able to find mates, so a relatively high rate of male aggression is favoured by sexual selection. By reducing testosterone through castration and increasing it with injections of exogenous testosterone, scientists have shown that this behaviour is directly linked to the hormone. Critics, who might in other circumstances point out that clownfish choose their sex as they mature, rightly note that rats are not humans.
When it comes to our own species, Hooven asks: "How could we know if T masculinises behaviour directly through its actions on the brain or indirectly through the body – say, through its actions on increasing muscle growth – or both?"
The answer is that, as so often, people who have atypical hormone levels in development enable science to gain the kinds of insights that norms do not allow – in this case, differences, or disorders of sexual development. Testosterone is a versatile substance, capable of adapting or transforming as the situation demands. For example, for testosterone to trigger the development of male genitalia, it needs to be converted into a more potent androgen called dihydrotestosterone (DHT). It's the action of DHT in utero that causes a fetus to develop a penis and a scrotum.
That conversion can’t take place if a male is deficient in a protein called 5-alpha-reductase (the disorder is called 5-alpha-reductase deficiency, or 5-ARD for short). In such cases, the infant is born without external signs of maleness, and in areas where advanced medical care is not received, he is likely to be sexed as and brought up as a female, with all the social pressures to conform to femininity that entails. However, in many cases, male genitalia do develop in puberty, because of the extremely high levels of testosterone – and it’s common for “girls” with male testosterone levels to then transition to the boys they always felt themselves to be.
In the 1970s, endocrinologist Julianne Imperato-McGinley studied groups of people with 5-ARD and concluded that "androgen [that is, testosterone] exposure of the brain in utero, during the early postnatal period and in puberty, has more effect determining male gender identity than does sex of rearing".
Again it's a conclusion that is disputed, but some things are clear. Males have much higher levels of testosterone than females. A female with the highest levels of testosterone will still have at least 10 times less than a male with the lowest levels. This distinct difference only fades in people with extreme health conditions or who are taking drugs to manipulate hormone levels.
Testosterone is secreted by the testes and some people are born with testes that never descend but remain within the abdomen. In some cases, their genitalia will tend to look more female than male, although they produce male levels of testosterone. A famous case is the female South African 800m Olympic double gold medallist Caster Semenya.
Semenya was assigned female sex at birth but has XY chromosomes, the combination that normally causes one to develop as male. Since her Olympic triumphs in 2012 and 2016, she has fallen foul of rule changes governing testosterone levels in athletes with certain differences of sexual development. This meant that she would have to take medication to lower her testosterone level, and she protested that it made her feel "constantly sick". She has appealed against the ruling in front of several bodies, without success, and earlier this year filed an appeal at the European Court of Human Rights.
If nothing else, what Semenya's case demonstrates is that sex classification is not a straightforward issue. A whole range of biological, social and cultural factors are involved, to say nothing of an individual's subjective experience and feelings.
As Hooven emphasises, endocrinology does not of itself tell us whether athletes such as Semenya should compete in the female category. But it does tell us a lot about a person's physiology and, unsurprisingly, is therefore a determining factor in how sporting authorities make that decision.
It also tells us how much hormones, in particular testosterone, do influence performance. Men's T levels are 10 to 20 times those of women, except in cases of differences of sexual development, of which 5-ARD is one example. It has been estimated, writes Hooven, "that people with these conditions are over-represented in elite female sports by 140 times, compared with the prevalence in the general population".
Another condition that causes high T in women is polycystic ovarian syndrome (PCOS), which can result in five times the normal female amount of testosterone – though still only half of the lowest end of the male range. As Hooven suggests, such figures would lead us to expect to find an over-representation of women with PCOS in elite sport. And sure enough, one study of 90 Swedish female Olympians found that 37 per cent had PCOS, which is about three times the general population rate in the same age group.
Trans women ‘advantaged’
All of which leads us back to Hubbard. Hooven doesn't express any opinion on whether transgender women should be allowed to compete in the female category in elite sport. Her book is carefully written, and she is always alert to the sensitivities and controversies into which her field inevitably intrudes. But she says although she is not about to recommend any given course of action, on the science she is unwilling to be bullied into silence.
"I won't comment on whether it's fair, but I can comment on whether trans women, who have experienced male puberty, would have an advantage, on average, in most sports over natal females: yes they do."
That isn’t an anti-trans sentiment but a pro-fact one. Of course, what’s done with the facts is another matter, and any course of action should be decided through open debate and respect for all those involved. There also needs to be an understanding that whatever happens, not everyone is going to be happy with the outcome.
Science does not stand apart from society. History tells us that scientific research is constantly informed and influenced by the changing mores and preoccupations out of which it grows. Yet it remains the best tool we have to gain the most objective understanding of reality.
In almost no sport do women have an advantage over men. Nearly all elite male athletes are better at what they do than nearly all women. But almost no elite female athletes (with the exception of long-distance cold-water swimmers) are better than elite male athletes. This is not an accident or a coincidence, or the product of cultural determinism or the patriarchy (although you might argue that competitive sport itself is a patriarchal invention), but an irrefutable fact of biology. And even with the best will and the most effective hormone treatments, biology cannot be retrospectively negated.
As things stand, a historically poorly understood hormone has been mythologised, demythologised, remytholigised, downplayed, overplayed and seen as a kind of biological red herring by the nurture-school of thought and as a vital key to our identity by those who give the edge to nature.
But however we choose to view testosterone, it remains an extraordinary piece of biochemistry. There’s much that we still don’t know or fully understand about T. That’s a good reason to find out more rather than to ignore what’s been established.
This story was first published in the August 14, 2021 issue of the Listener.
