University of Pennsylvania swimmer Lia Thomas has spent the last few months shattering school and Ivy League records for women’s swimming. These accomplishments have made news because Thomas is transgender and as recently as 2019 competed as a man. In the 1,650-meter freestyle event, Thomas beat second-place Anna Karandadze by a whopping 38 seconds.

After a wave of public criticism, Thomas swam again but this time lost to Yale swimmer Iszac Henig, who is also transgender (but female-to-male). One of Thomas’ teammates subsequently told journalists that she was confident Thomas and Henig colluded, with Thomas having intentionally lost in order to “prove” that transgender women do not have unfair advantage over biologically female athletes.

Whether the collusion actually happened is unclear, but regardless, the ongoing controversy surrounding Thomas’ participation in women’s sports is part of a wider and growing trend. Between 2017 and 2020, two female-identified but male-born runners in Connecticut won a combined 15 trophies in girls’ track, sparking criticism—and a federal lawsuit—from local high school girls and their parents. In 2021, transgender weightlifter Laurel Hubbard competed in the women’s category at the Tokyo Olympics. Hubbard had won gold in the women’s competition at the Australian International a few years earlier, and critics argued that her participation in the Olympics unfairly displaced the Tongan (biologically female) Kuinini Manumua, who otherwise would have qualified.

On one level, the debate over whether and how to integrate transgender girls and women into female sports is about striking a reasonable balance between accommodating a tiny subset of athletes with debatable natural advantages and ensuring basic fairness and safety for non-transgender participants. On another level, it is a proxy battle for the more fundamental question of what makes us male or female.

Until last week, the National Collegiate Athletic Association (NCAA), whose bylaws govern Ivy League swimming, required that transgender women submit to a year of testosterone suppression before they can become eligible to compete in the women’s category. State athletic conferences like the one under review in Connecticut have embraced this approach. Last November, the International Olympic Committee (IOC) took a stronger pro-trans-athlete position, announcing that it would henceforth consider policies that automatically mandate hormone-level verification for transgender women an affront to “human rights” and “inclusion.”

Facing blowback over the Thomas affair (and doubtless other incidents that did not make the news), the NCAA has now decided that it would delegate responsibility for setting transgender guidelines to individual athletic organizations. Decisions over who should count as female, goes the new thinking, should be made on a sport-by-sport basis, taking into account the impact of transgender women’s physical traits on competitive fairness and safety in each particular sport. If the national organizations—such as USA Swimming—do not come up with criteria of their own, then those of the international body governing that sport apply. And if these do not exist, then the NCAA will defer to IOC guidelines (which, to repeat, seem even more lax than the NCAA’s now-renounced policy). In short, the NCAA’s new policy combines a sensible case-by-case, one-size-doesn’t-fit-all approach with an all-too-convenient refusal to take a principled, evidence-backed stance on a hot political controversy.

It’s worth noting that the NCAA’s now-discarded approach of hormone suppression for one year, which received the endorsement of high-profile transgender-advocacy organizations including the American Civil Liberties Union (ACLU), lies in tension with the philosophical claims of the transgender movement. Contemporary transgender activism is distinctive in its insistence that gender identity is the sole determinate of whether a person is male or female. Transgender women, so the argument goes, really are and always were women; medical interventions such as hormone therapy confirm, but do not change, a person’s gender.

It would follow from this that any restriction on the ability of transgender women to participate in women’s sports is arbitrary and unjust. A woman who happens to have been born with a “male” body—there is, we are told, no such thing as a male or female body—has no more of an unfair advantage than a biologically female basketball player who is unusually tall. Some fringe activists do argue that self-identification alone should be enough to qualify one as female, but mainstream progressive advocacy groups have preferred to take the more “pragmatic” (albeit philosophically incoherent) road.

In the United States, where transgender policy is heavily shaped by litigation (or the threat thereof), transgender advocates have effectively proposed two conflicting definitions of “sex”: one for sports and another for nearly every other policy matter. When student access to bathrooms was at issue, the argument was that any association between gender status and body type constituted unlawful “stereotyping.” But when the issue turned to athletics, the argument was that blanket bans on transgender women in women’s sports are overly broad—thus conceding that it is legitimate to exclude at least some female self-identified athletes from women’s sports.

Setting aside the philosophical tensions, policies like the one enforced by the NCAA until last week run against the grain of current scientific knowledge about sex differences and their impact on athletic performance. Transgender advocacy groups have been anything but a paragon of clarity and honesty on this issue, cherry-picking studies, omitting inconvenient qualifications, and taking conclusions out of context. For example, On the Team: Equal Opportunity for Transgender Student Athletes, a policy handbook coauthored by the National Center for Lesbian Rights and the Women’s Sports Foundation and endorsed by the influential Gay, Lesbian, and Straight Education Network, confidently asserts that the belief that transgender girls and women can compete outside of the normal range of female capability after completing a year of hormone suppression “is not supported by the evidence.” What the authors neglect to mention is that the study on which they rely in support of their conclusion clearly states that existing research can neither confirm nor refute transgender advantage.

A more recent review of the research on sex differences in sports by Emma Hilton and Tommy Lundberg paints a different picture, one more in line both with common sense and with recent experience. The paper suggests that transgender women need not lose their natural advantages after hormone suppression, at least not in the way that athletic and advocacy organizations have assumed. Hilton and Lundberg list the advantages conferred by male puberty as including

larger and denser muscle mass, and stiffer connective tissue, with associated capacity to exert greater muscular force more rapidly and efficiently; reduced fat mass, and different distribution of body fat and lean muscle mass, which increases power to weight ratios and upper to lower limb strength in sports where this may be a crucial determinant of success; longer and larger skeletal structure, which creates advantages in sports where levers influence force application, where longer limb/digit length is favorable, and where height, mass and proportions are directly responsible for performance capacity; superior cardiovascular and respiratory function, with larger blood and heart volumes, higher hemoglobin concentration, greater cross-sectional area of the trachea and lower oxygen cost of respiration.

Because male advantage is at least as much due to having gone through puberty as having higher levels of testosterone, that advantage, the authors report, diminishes but hardly disappears following a year or even several years of testosterone suppression.

Consider muscle mass, where natal males have, on average, a 40 percent baseline advantage over natal females. Testosterone suppression results in a reduction of between 3 and 5 percent in muscle mass after one year and up to 12 percent after three years, with no study ever reporting a larger reduction. Differences in strength are even more significant, as they are a more accurate proxy for athletic performance. After 12 months of hormone treatment, transgender women experienced a 4 percent drop in grip strength but retained a 17 percent advantage over transgender men (i.e., natal females).

Such statistical disparities may seem small, but at the top level of athletic competition they give those who went through male puberty a critical edge. Contrary to the assumptions of the NCAA, the ACLU, and the federal courts, hormone levels alone are a poor proxy for predicting athletic advantage. Puberty seems to play at least as significant a role, though with important variations between types of sports.

Hilton and Lundberg might agree with the NCAA’s new approach. As they write, “it is clear that different sports differ vastly in terms of physiological determinants of success, which may create safety considerations and may alter the importance of retained performance advantages. Thus, we argue against universal guidelines for transgender athletes in sport and instead propose that each individual sports federation evaluate their own conditions for inclusivity, fairness and safety.” Exactly how individual sports associations will balance the demands of transgender “inclusivity” with those of fairness and safety for all remains to be seen.

Critics of policies such as the one that permitted Thomas to compete in women’s swimming should be clear about what they object to, and why. If the goal is to ensure fairness and safety in women’s sports, then perhaps a blanket ban on participation by male-born but female-identified athletes is unnecessary. After all, within this category one can find a small number of individuals who transitioned before puberty, and who therefore did not develop the traits that would otherwise place them outside the range of normal female performance. (Of course, whether such individuals really are female, and whether they should have been put on the medical transition track before reaching maturity, are separate, and explosive, questions of their own.) A sport-by-sport approach is certainly more reasonable.

Blanket bans restricting participation in women’s sports to biological females may also prove strategically unwise, as Idaho’s experience with the Fairness in Women’s Sports Act demonstrates. In 2020 the District Court of Idaho placed a temporary injunction on enforcement of the Act. The ACLU, which litigated the case on behalf of transgender athletes, easily convinced the court that the law was unconstitutionally broad. As a result, the policy of allowing transgender women to compete against non-transgender women following a year of testosterone suppression now has the imprimatur of the courts—not to mention the aura of “civil rights.”

But if the goal of criticism is to expose transgender “inclusion” in women’s sports as a thinly veiled effort to bring about a more radical social and cultural change—something transgender advocates will readily and openly concede when they are not talking to mainstream liberals—then critics should meet their adversaries on that level.

Progressive advocacy groups already accept that not all transgender girls and women should be included in the female category of sports. For policymakers seeking a pragmatic-accommodationist approach, the key question is not whether limiting transgender women’s participation in female sports is “equitable,” but whether the current line-drawing makes sense. Above all, policymakers should be skeptical of efforts by advocacy groups to frame these debates using abstract “rights talk” and empty platitudes about “inclusion.” The NCAA’s revised policy could prove to be a step in the right direction, provided the subordinate athletic associations follow current scientific knowledge and common sense and not bend their knee to ideologues.

Photo by Hunter Martin/Getty Images


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