Y It Matters

When It Comes to Strength & Speed, It Matters a Lot

The 2011 documentary Too Fast to Be a Woman?: The Story of Caster Semenya tells the story of a loving South African family celebrating the successes and challenges in the life of their daughter Caster, a gifted runner who becomes entangled in legal wranglings regarding gender eligibility in women’s sports. The film puts a human face on the thorny controversy that pits questions of fairness against inclusivity as these contending issues play out in the life of an athlete raised and identifying as a female while possessing a male genome.

Developmental Differentiation

In embryonic development, following the fusion of two gametes—an egg and a sperm—the resulting human zygote possesses a unique genome, or genetic library, comprised of 23 chromosome pairs. Each chromosome is a strand of compacted DNA which will be selectively unraveled and activated to synthesize the singular organism that will emerge as a fully developed newborn at birth. Set 23 is the sex pair of chromosomes, with an XX karyotype normally resulting in a physiological female and an XY karyotype producing a male. Genes, interacting with the influences of environmental factors, such as in-utero health and later nutritional status, determine our physical characteristics, such as height, eye color, reproductive anatomy, and blood type. These physical features constitute our phenotype (observable physiological traits), and it is self-evident that the female and male genotypes, XX and XY, produce distinct and universal patterns in female and male phenotypes.

Caster Semenya has a mutation-derived inborn error of metabolism known as 5a-reductase type-2 deficiency (5aR2D). During normal early-embryonic development, the enzyme 5a-reductase type 2 (5aR2) catalyzes the conversion of testosterone to 5a-dihydrotestosterone (DHT), a potent hormone which is critical for the initial differentiation of male sexual anatomy. In individuals with 5aR2D, the resultant deficiency in DHT impairs embryonic genital formation in males, thus resulting in a spectrum of outcomes from feminization to anatomical ambiguity to less severe and surgically correctable defects such as penile malformation. Also, testicles may be present but remain undescended, positioned inside the lower abdomen rather than externalized into a scrotum.

Consequently, 5aR2D is an example of a genetic anomaly which can result in someone who does not fit into the clean, binary categories of male or female—a true intersex condition. There are other intersex conditions as well, and thankfully, all are rare. As was the case with Semenya, the infant may be raised as a female based on the appearance of the predominant phenotype. In an interview, Semenya’s grandmother commented that she knows her granddaughter is a girl “because we changed her nappies.” Early-life photographs of Semenya show a beautiful and happy baby girl in a dress.

Puberty

But with 5aR2D, things get more interesting at puberty. If a 5aR2D individual has male gonads, he will undergo normal virilization beginning at about age 11 or 12, when the testicles begin secreting a high level of testosterone. Healthy adult males will typically have seven to eight times higher serum testosterone concentrations than do healthy females. And since the development of a male’s secondary sex characteristics at puberty is driven by the anabolic properties of testosterone, rather than by DHT, the growing adolescent body is masculinized, resulting in, among other things, a lower voice, higher muscle mass, higher cardiac output, and enhanced bone density.

Undeniably many of these changes afford advantages over XX females in athletic performance, especially for endeavors contingent upon strength and speed. As a result of their metabolic and subsequent physiological transitions, as well as psychological developments—as testosterone surges, they often find themselves feeling attracted to females—many individuals with 5aR2D embrace a male persona sometime after puberty. When we suspect by observing Caster Semenya’s androgenic facial features, deep voice, and muscular build that she may not be a genomic female, our senses and our intuitions are not deceiving us.

The documentary on Semenya features commentary by scientists and sports physiologists speaking from the impressive authority of titles, lab coats, and a clinical interview setting. What is never asked nor answered directly is if Semenya’s genome is XX or XY, or whether the gonads producing the hormones that have led to her impressive athletic performances in women’s track events are ovaries or testicles.

The Boxing Match Seen ‘Round the World

In August, a 46-second boxing match thrust the intersex issue into the broader mainstream consciousness. Olympic viewers around the world witnessed XY boxer Imane Khelif of Algeria pound his fist into the face of Italy’s XX female boxer Angela Carini in the first round of the women’s welterweight division. Although both Khelif and Taiwanese boxer Lin Yu-ting had previously been disqualified from fighting females by the International Boxing Association, the International Olympic Committee permitted both of them to fight in the women’s divisions, despite their having failed prior gender-eligibility tests, which indicated positive for Y chromosomes.

Khelif reportedly has Swyer Syndrome, also known as XY gonadal dysgenesis, a condition in which male gonadal tissue is diminished or absent, resulting in embryonic feminization. As in cases of 5aR2D, at the onset of puberty, a female-appearing child with Swyer Syndrome can undergo virilization with the growth of a characteristically male physique and enhanced athletic-performance capabilities.

In a specter similar to post-race photographs of Caster Semenya, the appalling image of Khelif looking unmistakably masculine, while towering above a collapsed and sobbing Carini, viscerally calls for a more careful and thoughtful deliberation over the question of competitive fairness in athletics.

Bodies, Not Identities

In a fight or in a race, it is bodies, not identities, that step into the ring or up to the starting line. When XY transgender Anne Andres took first place in the women’s division at the 2023 Western Canadian powerlifting championship, smashing records by hoisting 597.5 kilograms—210 kg more than the second-place XX female—it was a feat attributable to his objectively male body, not to “her” subjectively female identity. Assuming fairness to be an earnest consideration in athletics, should anyone endowed with an XY genome be allowed to compete against XX females?

Many sports-governing bodies attempt to assuage the controversy by disallowing athletes with elevated levels of testosterone in female-identifying athletes, as if the question of gender could be reduced to the level of a single hormone. This is myopic and simplistic. It fails to consider how XY puberty builds a male body and mind in ways that later surgical or chemical castration cannot unbuild, or how a female body, likewise, cannot be induced to construct a fully male phenotype merely by supplementing it with testosterone. It does not consider how the most basic subunit that distinguishes between male and female at conception, the 23rd chromosome, is encoded into every one of the more than 30 trillion cells comprising the human body. It ignores how the spate of transitioned men recently taking the podium in women’s swimming, powerlifting, golf, fencing, and bicycling were not girly biological boys who allegedly transitioned as children, nor are they individuals with intersex conditions, but rather are physiologically normal adult men who have moved from competing against men to competing against women, taking with them not only a Y chromosome from their fathers, but also the formative experiences of having grown up socially and culturally as males.

A Fair & Inclusive Solution

Ever since William “Lia” Thomas, a 6’4” biological male, began winning national championships in women’s swimming in 2021, the question has become a touchstone in the cultural wars. It has also moved the question of the “Y” from a conundrum regarding people with rare genetic anomalies to an issue critical to the integrity of—indeed the very future of—women’s sports.

Athletic competition is an enterprise of manifest objectivity. Records and wins are quantified in exacting measurements of time, space, and matter. The scoring in combat sports, figure skating, and gymnastics is numerical, with judges expected to be prepared to defend their decisions against standardized criteria.

Rules and exclusions regarding eligibility are an indispensable part of sporting competition in much the same way that laws are critical for a functioning civilization. Laws and regulations are among the tools by which a society applies wisdom to the task of ordering life together in resonance with the natural and moral order. There are good reasons we have highway speed limits and statutes prohibiting theft, and there are good reasons why blood doping and synthetic steroids are banned in athletics. There are good reasons why combat sports are fought in weight-specific categories, and there are good reasons why Masters events require entrants to have been born before a certain date. And there are good reasons why girls’ and women’s sports have historically been—and should continue to be—inclusive only of those with no “Y” in their karyotype. 

In reality, the call to erase objective gender distinctions is not about sports at all. It is a proxy war against our conception of reality. Gender fluidity proposes that the created order is either an illusion or a construct masking power. In a battle as old as the Garden of Eden, it is a manifestation of the recognition that we cannot be gods so long as God alone is God. No one wins in this kind of a war, and as gender boundaries are blurred in athletics, it is women and girls who are becoming the first casualties.

Genomic verification need not be burdensome. No genital exam or serum blood quantification of testosterone is necessary. Chromosome detection can be confidently determined once, and at a low cost. Within the past decade prenatal screening, now usually done before 12 weeks’ gestation and often prior to heartbeat detection, has become the standard of care in most obstetrical practices. In addition to screening for genetic diseases the testing package includes sex determination, which the expectant mother is invited to check via her smartphone using a private QR code, or she may delegate the knowledge to a trusted relative or friend for the ever-popular practice of a “Gender Reveal” celebration—a tacit cultural acknowledgement of a reality humans universally and instinctively recognize as true.

With an objective rule for eligibility, female sports can continue within a respectful and protective boundary based on what best distinguishes a female from a male—the XX. And with no apologies to anyone it offers to those with the “Y” the option of competing either in an open category or as males. 

And with that we align ourselves with reality and with the created order.