NOTE: This is a chapter from my book ‘Born in the Right Body‘, which is based on my 2020 critique of inclusion of male athletes in female sport. The book chapter focuses more on inclusion rules, whereas the original article explores the issue of male DSDs in more detail. The articles complement each other so I recommend reading them both.

Humans are a sexually dimorphic species. This means that apart from reproductive and chromosomal differences, there are observable differences in appearance that account for why men are on average bigger, faster and stronger than women. Depending on the variable, there is more or less of an overlap between the sexes. Some women are taller and have more muscle than an average man and some men are shorter than an average woman, for example. However, these are the outliers. Overwhelmingly, men are able to dominate women due to superior strength, speed and aggression, and both endemic male violence against women and the fact that male athletes outperform female athletes in virtually every category, are stark reminders of this.

Due to the gendered power imbalance, sport has always been male-focused. Women’s sport was created only recently, due to the advancement of women’s rights and a recognition that without sex-segregated categories, there is little, if any, chance of fair play for women and girls.

It may therefore come as a surprise that today, males are allowed to compete in female sporting categories.

History of biological males in women’s sport

From the outset, women’s sport struggled to ensure female-only competition, mainly due to the inclusion of males who either masqueraded as women, underwent sex-reassignment surgery or had Disorders of Sex Development (DSDs).

As a result of these males outperforming women, in 1968, the International Olympic Committee sought to ensure fair play in women’s sport by mandating on-site “sex checks” for female athletes. These initially consisted of visual observation and gynaecological exams, but this was quickly abandoned in favour of the much less traumatic genetic testing, which initially looked for X-chromatin (second, inactive X chromosome) as proof of female sex, and later on, the Y-chromosome as evidence of male sex. 

This practice continued, not without controversy, until 1998. (Elsas et al, 2000)

Because chromosomal sex checks could not differentiate between different DSD conditions – some of which gave 46 XY DSD males a female appearance and an insurmountable performance disadvantage compared to elite males – these tests were seen as imperfect and discriminatory. Therefore, following a prolonged campaign for the rights of DSD males to compete as women, chromosomal sex checks were abandoned in 1999, and replaced with testosterone suppression rules, which limited testosterone levels in female competition to below 10 nmol/L.

This, by far, exceeds the normal female serum testosterone range of 0.5 – 2.4 nmol/L (with female testosterone levels in excess of 6.9 nmol/L being indicative of a serious disease such as adrenal or ovarian tumours). However, it has allowed the inclusion of DSD male athletes as well as female athletes with medical conditions that raise their testosterone above normal female level, in women’s sport.

By convention, both female athletes with raised testosterone, and DSD male athletes with testosterone level in the male range, were referred to as “females with hyperandrogenism”. So when studies were published claiming that there was an overlap in serum testosterone between elite men and elite women, it was not clear whether this was a bona fide physiological overlap between the sexes or if it resulted from the female category being inherently mixed-sex.

Testosterone doping, and the fact it can suppress endogenous testosterone in males leading to low levels, could have also affected these results.

In 2014, Ferguson-Smith & Bavington published a paper arguing against the testosterone suppression rules. 

The authors noted that the incidence of 46 XY DSDs is less than 1:20 000 in the general population, yet these conditions are present in 1:421 female athletes.

Most of these DSD athletes either had complete or partial androgen insensitivity. 

In addition to 46 XY chromosomes, athletes with complete androgen insensitivity syndrome (CAIS) have high levels of circulating testosterone, to which their bodies are almost completely resistant so they were exempt from testosterone suppression rules. The athletes with partial androgen insensitivity (PAIS) however, had to undertake measures to lower their testosterone, either by having their testicles removed before entering competitive female sport, or by taking testosterone suppression drugs. 

As a result of the sporting performance of CAIS and PAIS athletes being found to be comparable, while their testosterone levels were very different, the authors argued that the performance advantage of 46 XY DSD athletes cannot be due to testosterone.

Looking at gender verification reports, they also noted that 46 XY DSD athletes, in general, were closer in stature to the average male, and that they had greater lean body mass than females. 

Males who have two Y chromosomes – such as 47 XYY – are particularly tall. On the other hand, 46 XX DSD females who have masculinised appearance, still have female body habitus. Therefore, the tall stature found in 46 XY DSD athletes appears to be associated with genes on the Y chromosome, or the modulation of stature genes found on autosomes by the Y chromosome. 

In their paper, Ferguson-Smith & Bavington acknowledged that the Y chromosome was not the only factor contributing to taller stature, and that sporting advantage was likely to be multifactorial. 

However, the evident male/female sex-differences in athletic performance across almost all sports, and even in the pre-pubertal stages of child development (Marta et al, 2012), suggest that no practical intervention could fully mitigate the sporting advantage conferred by the Y chromosome itself. 

At this point, the logical conclusion should have been to abandon testosterone rules, return to genetic testing in order to ensure women’s sport was female only, and create a third category where 46 XY DSD athletes could compete fairly and without being forced to suppress their testosterone.

Instead, the authors called for withdrawal of the “regulations on hyperandrogenism”, but instead of arguing for the third category, they claimed that “tallness, whether determined by genes on the Y or any other chromosome, offers an example of an acceptable variable that contributes to athletic success in elite female athletes including those with 46,XY DSD” and that there was “no evidence” 46 XY DSD male athletes “possess any physical attribute relevant to athletic performance that is neither attainable nor present in 46,XX women” (Ferguson-Smith & Bavington, 2014). 

In the wake of ongoing controversy, Indian sprinter Dutee Chand claimed that because there were no testosterone suppression rules in men’s sport, that these rules in women’s sport constituted sex-based discrimination. I don’t know the details of Chand’s medical history, but based on articles I could access, Chand appears to have a 46 XY DSD. 

Chand won the sex discrimination case, and in 2015, the testosterone suppression rule for “females with hyperandrogenism” was overturned. 

At the same time, the IOC ruled that normally sexed trans-identifying males could be included in women’s competition too, as long as they professed to have a “female gender identity” and could demonstrate that their serum testosterone level has been below 10 nmol/L for at least 12 months prior to their first competition. (International Olympic Committee, 2015).

The following year, all three medalists at the Women’s 800 metres competition in 2016 Olympics in Rio, were 46 XY DSD males. 

Following the race, the three female competitors, who missed out on the medals, embraced in defeat and said, “We see each other week in, week out, so we know how each other feel”. 

Lynsey Sharp, who came sixth, broke into tears and said that, “It was difficult to compete against Caster Semenya and other hyperandrogenic athletes after the rule to suppress testosterone levels was overturned.” She also complained that the athletes were effectively competing in “two separate races”. 

Many spectators empathised with the female athlete’s predicament. However, the IAAF General Secretary Pierre Wiesse’s dismissed their concerns by saying that Caster Semenya, was “a woman, but maybe not 100 per cent”.

Although the details of athletes’ medical history were not publicly known at the time, Caster Semenya appears to have been born with 5-ARD (5-alpha-reductase deficiency), which is a male DSD caused by an X-linked genetic mutation. Babies with 5-ARD have 46 XY chromosomes and testes, however, due to a genetic defect, their bodies don’t produce enough of the steroid 5-alpha reductase 2 – an enzyme which drives the development of male genitalia before birth.

Consequently, male babies with 5-ARD are born with ambiguous genitals, a micropenis, hypospadias or even female-appearing genitals. They can sometimes be mistaken for girls, or deliberately raised as girls, but if they are allowed to develop normally and their testicles aren’t removed in a “gender assigning” procedure, the surge in testosterone at puberty will result in masculinisation of the body and an associated sporting advantage over female competitors.

Following the debacle in Rio, studies found that a natural serum testosterone level did confer sporting advantage in certain women’s events, after all, and in 2018 the rules were changed yet again.

The new testosterone limit for androgen-sensitive DSD male athletes was set at 5 nmol/L, whereas biologically female athletes, and DSD male athletes who were completely resistant to testosterone, were exempt.

Having dominated female athletic competitions whenever they were not required to suppress testosterone, double Olympic 800m champion Caster Semenya’s sporting advantage was reduced with testosterone suppressing drugs, which also caused significant side effects. Therefore, Semenya issued a legal challenge, asking for the testosterone suppression rule to be removed.

In 2019, Court of Arbitration for Sport upheld testosterone suppression rules, stating that 46 XY 5-ARD athletes – such as Semenya – have “circulating testosterone at the level of the male 46 XY population and not at the level of the female 46 XX population. This gives 46 XY 5-ARD athletes a significant sporting advantage over 46 XX female athletes.” (Mokgadi Caster Semenya v. International Association of Athletics Federation, 2018; Ingle, 2019)

Semenya appealed this decision at the Swiss Supreme Court in 2020 and lost. This meant that Semenya wasn’t able to defend Olympic 800-metre title at the Tokyo Olympics in 2021, or compete at any top meets in distances from 400 meters to the mile, unless they agreed to lower their testosterone level through medication or surgery. (Dunbar & Imray, 2020)

Semenya continues to pursue this case at the European Court of Human Rights.

Meanwhile, the IOC announced that normally sexed trans-identified males were allowed to compete in women’s categories at the 2020 Tokyo Olympics, subject to 2015 rules that required them to profess a “female gender identity” and have evidence that their testosterone didn’t exceed 10 nmol/L for 12 months. 

It appeared that the transactivist strategy of conflating sex with gender – and DSD with transgender – had finally succeeded. If gender identity and femininity, rather than biological sex, determined whether an athlete was male or female (a concept that has already been validated through the inclusion of DSD males in women’s sport), then privileges reserved for DSD males could arguably be extended to normally sexed males who identify as women.

Several high profile female athletes and coaches spoke out against the escalating unfairness and compromised safety of female athletes under the new rules. Others remained silent for the fear of losing sponsorships and their place on the team. 

Scientists such as Dr Emma Hilton reviewed the available evidence and confirmed that male sporting advantage is significant – ranging from 10-50% depending on the sport – and it cannot be removed by testosterone suppression, especially in the case of males who went through normal male puberty. (Hilton & Lundberg, 2020).

None of this made much difference. Ever since 2016 when trans-identifying males were allowed to compete “as women”, they’ve dominated female competitions, even if they only ever had mediocre success while competing with other men, and were much older and less fit than their female competitors. When these males were allowed to participate in contact sports, women suffered serious injuries such as broken bones (Ralph, 2017) and skull fractures (Presley, 2021).

For a while, things looked pretty grim for female athletes. Sporting authorities seemed swept up in narratives of “inclusion” and the “human right” of certain males to compete with women, while sports commentators around the world celebrated the records these males were setting in women’s sport. 

Eventually, USA Powerlifting and then World Rugby banned trans-identifying males from women’s competition (World Rugby, 2021). For this, both organisations were vilified by transactivists, who maintained that “inclusiveness” was all important, while safety and fair play for women and girls was secondary. As a result, most other sporting associations have given in to transactivist demands.

This culture war reached fever pitch during the Tokyo Olympics, which saw several trans-identifying males compete in female categories, including a trans-identifying male athlete who was a part of New Zealand’s weightlifting team. Even though this athlete didn’t win a medal – and some commentators remarked on apparent lack of effort during this competition in comparison with their previous results – their qualifying meant that a female athlete was deprived of a once-in-a-lifetime opportunity to compete at the highest level (FPFW, 2021).

All over the world, spectators and athletes of both sexes were shocked at the disrespect both the New Zealand weightlifting team and the IOC showed for fair play and women’s sport. However, both organisations doubled down on their questionable decisions. The trans-identifying male weightlifter from New Zealand was given a “Sportswoman of the Year” award by the University of Otago, while the IOC decided to abandon the testosterone suppression rule altogether. 

Since then, the controversy has moved to the University of Pennsylvania swimming team, which has allowed a trans-identified male swimmer to compete against women, resulting in never before seen records (Lohn, 2022), accusations of indecent exposure in the female changing room (Lord, 2022) and ongoing protests by female athletes (Rushing, 2022).

If women athletes thought they had it bad under the new rules, wait until they see the new-new rules, which dispense with any pretence of caring about women’s safety or fair play. Women’s sport is now open to any man who claims he feels like a woman, and it is up to the individual sport to decide where the boundaries lie, in a febrile climate that is rife with cancel culture and spurious accusations of transphobia. (International Olympic Committee, 2021).

The Platonic ideal

As far as I can tell, the rationale for inclusion of male athletes in women’s sport has always been two-fold – unfavourable comparison to the Platonic ideal of a man, and compassion for their predicament.

Growing up, many DSD male athletes have either a female or an androgynous appearance. They are often raised as girls and their superior athletic performance in female competitions contributes to them being chosen for teams and sporting events. 

Now imagine what it must be like to be raised believing you were female, perhaps even an athletics champion, only to discover that the reason you performed so well is because you are biologically male?

Not only does this cast a shadow on your sporting achievements, it changes the way you think about yourself and your future. As females we expect to become mothers and we are treated a certain way by society. Learning that we are in fact male not only shatters perceptions and expectations we and others may have had, but learning that our biological sex is the opposite from what we thought it was has an impact on our sexual orientation and relationships with others. 

Furthermore, just because DSD male athletes have a natural sporting advantage, it doesn’t mean that they haven’t worked as hard as female athletes. Should these athletes, at the height of their career, be reduced from a national hero to some kind of a “cheat”, and their DSD diagnosis broadcast to the world? 

Campaigners for the inclusion of trans-identifying male athletes harnessed this ethically sensitive situation to influence discourse around sex-segregation. 

If a man is sufficiently “feminine” – for example if he has breasts and long hair, wears makeup and skirts, takes female hormones or uses a female name and female pronouns – then it would be “cruel” to not let him compete in a female category. After all, what female athletes and both feminine and feminised male athletes have in common, is that they cannot outcompete elite males. Therefore, the only chance these males have to compete at an elite level is if they are allowed to compete in a female category. 

Are 46 XY DSD athletes biologically female?

In humans, sex is determined by the presence or absence of the Y chromosome. This is because all humans have an X chromosome in their genetic make up, but only males have a Y.

Normally, males have 46 XY karyotype, a penis, testicles and produce sperm, while females have a 46 XX karyotype, a vagina, uterus, ovaries and produce eggs. However, because the Y chromosome contains genetic information necessary for the embryo to develop into a male, even individuals with atypical karyotypes such as 47 XXY, 47 XYY or 49 XXXXY will be male, while 47 XXX or 45 X0 individuals will be female.

There are many different genetic abnormalities that can give rise to Disorders of Sex Development (DSD). Sometimes, genes on the Y chromosome – such as the SRY gene which is involved in the development of testicles – can be deleted or even “jump” onto the X. Or genes on sex chromosomes or autosomes, which play a part in sex differentiation, can mutate. One of these genes is an androgen receptor gene which is found on the X chromosome and mutations can result in partial or complete androgen insensitivity (PAIS and CAIS). Very rarely, DSDs can also arise when two or more fertilised cells merge during very early development. As a result, the person has multiple karyotypes throughout their body, and this can mean a mixture of male and female cell lines. (Dumic et al, 2008)

As a consequence of these genetic abnormalities the developing embryo can receive erroneous signals, or fail to receive appropriate ones, and subsequently develop ambiguous genitalia, some opposite sex reproductive structures or absent or non-functional gonads, and in some cases, a male body could feminise while a female body could masculinise. 

Traditionally, it was assumed that embryonic development is sex-neutral until gonads (ovaries or testes) start to develop and secrete sex hormones, which directs the body’s development down the sex-appropriate pathway. However, if a male foetus is resistant to testosterone, or it fails to masculinise for some other reason (or if a female foetus inappropriately masculinises) the genetic sex of such an individual will be at odds with their appearance (phenotype).

Because our external appearance drives both self-perception and how others see us, 46 XY DSD males with a female phenotype typically have a female gender identity and are socially considered to be women, while 46 XX DSD females with a male phenotype typically have a male gender identity and are considered to be men. 

This mismatch between genotype and phenotype, as well as other sex ambiguities, gave rise to the myth that people with DSDs are “intersex” (between male and female), that they are “hermaphrodites” (both male and female), or “pseudohermaphrodites” (an outdated medical term for a mismatch between external genitalia and gonads). It also led to claims such as “sex is a spectrum” and that a 46 XY person can be “female but maybe not 100%”.

However, in recent years it has been shown that sex chromosomes start to drive sex differentiation soon after fertilisation – way before gonads or sex hormones appear – and this affects all tissues in the body, including bones, muscles, blood, heart, lungs, liver, brain and so on. (Deegan & Engel, 2019; Lowe et al, 2015; Heydari et al, 2022)

This means that male-female sex differences are more fundamental than just physical appearance, gonads and sex hormones. They exist on a genetic and molecular level, are driven by different sex chromosome complements – X and Y for male, only X for female – and they produce physiological differences that explain why 46 XY DSD athletes have a male sporting advantage, despite incomplete masculinisation.

The way forward

Male sporting advantage is so significant, that even the arguably greatest female athlete of all time, Serena Williams, could not beat male tennis player Karsten Braach, whose ATP ranking was World No. 203 at the time of the match. Serena didn’t lose because she was a worse player. In fact she was much better, considering her outstanding successes in female competition. However, Braach was naturally stronger, faster and taller, which determined how hard he was able to hit the ball, reach far ends of the court and stretch to return. This natural physical advantage alone allowed him to beat the best female player at the height of her career. 

Another example is the famous doubles match in the final of 1977 US open between Martina Navratilova and Renee Richards – a biological male who underwent gender reassignment as an adult. The fact that Martina won is often used by transactivists to claim that the inclusion of normally sexed males won’t necessarily come at the expense of fair play for women. However, at the time of the match, Richards was 43 years old, which was 22 years older than Navratilova. Imagine if Richards entered women’s tennis in their youth, and played against elite females of the same age. The female players would not stand a chance. 

As we saw at the 2016 Rio Olympics, the inclusion of DSD males in female sport can have much the same effect. Even with testosterone suppression rules in place – because they neither apply to all events nor fully mitigate male sporting advantage – biologically male athletes are outperforming biological females in many events, and now the testosterone suppression requirement has been removed by the IOC altogether.

In my opinion, forcing DSD male athletes to undergo surgical procedures or take drugs they don’t need, in order to be eligible to compete with females, is as antithetical to the ethics of sport as doping. Therefore I support the rejection of testosterone suppression rules. However, addressing the unfairness toward DSD males, without addressing the unfairness toward female athletes, is not going to work in the long term. 

Furthermore, with transactivism conflating DSD and transgender in order to normalise the feminisation of males and masculinisation of females with hormones and surgery, it is only a matter of time before males who were gender-reassigned at the onset of puberty start entering female competitions. There hasn’t been such a case yet, but to make an educated guess, their sporting advantage will at least be comparable to DSD males. 

How will females who had undergone gender reassignment as minors and had their bodies masculinised compare to the feminised males? How will these females compare to normally sexed male athletes, considering that despite hormonal manipulation, their lack of a Y chromosome means that they can never attain the male sporting advantage?

Under femininity-based inclusion rules, it is likely that gender-reassigned females will be excluded on account of taking masculinising doses of testosterone, while feminised males will be permitted to compete in female sport. This might seem far-fetched now, but even if the practice of gender reassignment was to stop tomorrow, enough children have already been affected and we must anticipate this becoming an issue in the future. 

The reality is that both trans-identifying and DSD males are currently competing in the wrong sex category. Acknowledging this needn’t affect the social convention of referring to DSD males as “women”. However, there are areas where biological sex is relevant – and sport is one of those.

Male advantage of course depends on the sport, but regardless of whether the advantage is 10% or 50% it is insurmountable between opposite sex athletes of the same age and fitness level. In elite sport, there are only so many places on the team and on the podium. While the predicament of males who, for one reason or another, cannot compete in elite male sport rightfully evokes compassion, I would like the world to show the same compassion for females too. 

Female athletes have fought long and hard against prejudice and discrimination borne from their competitive disadvantage in relation to males. They have been ogled, infantilised, underfunded, sabotaged and sexually assaulted because of their female sex, by those of the male sex. Although these issues have, in some cases, affected biological males with a feminine appearance, I don’t believe this is a sufficient reason to justify making female sport a mixed-sex category.

I would like to reiterate that DSD males and trans-identifying males are not the same. They are different biologically and they face very different challenges. However, for the purposes of inclusion in female sport, the two are related in practice, if not in spirit, and ultimately female athletes pay the price.

Women and girls are half the population and they deserve to compete fairly. We also have hopes and dreams of standing on the podium, proving our worth, getting sponsorships, or scholarships, prize money and a career in sport. Our self-esteem, sense of self and future prospects are all affected by the way current rules prioritise male inclusion over fair play for women and girls. I am here to ask that our human right of having access to single-sex spaces, which by definition includes female-only sport, is respected. Without exception.

References

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