Allowing Biological Males in Women’s Sports is Scientifically Unsound

Published October 6, 2022


Having colleges or even the Olympics permit biological men to compete in women’s sports is one thing; pretending that it is fair, is something else.

There is no argument that a person’s sex is determined at the moment of conception, and that fertilization of an egg occurs with either an “X” or “Y” sperm cell, which will only determine one of two sexes. Following conception, the development pathways of males and females diverge immediately and substantially, right down to a cellular DNA level. These bifurcating pathways endure throughout an individual’s lifetime.

Every single nucleated cell in the human body has 46 sex-specific “XY” chromosomes (denoting biological male sex) or “XX” chromosomes (denoting biological female sex). These nucleated cells in turn have sex-specific functions which guide their development and biological function.

Indeed, sex is not just “skin deep.” It persists down to a microscopic, cellular level, and biological sex is indicated within the 100 trillion (or so) cells in the human body.

Bottom line: the indelible imprint of biological sex—determined in utero and at the moment of conception—is not scientifically or clinically possible to alter.

This physiological difference cannot be suppressed by any amount of synthetic hormones or “puberty blockers”—known scientifically as “gonadotropin-releasing hormone agonists.” HHS’s Office of Population Affairs (OPA) says their use in children is “safe” and “reversible” in its widely touted official, final guidance document. Recently, however, even the scientifically pliant FDA has warned the drugs can cause life-threatening brain swelling, headaches, vomiting, a host of visual disturbances (including blindness), and tumor-like masses in the brain. This admission made clear OPA’s dereliction of its duty to science. One doesn’t have to be a specially trained FDA drug safety expert to know that using pharmacology to fight the biological programming of trillions of nucleated cells in the human body is going to have serious consequences.

A recent review of two dozen medical studies published in the British Journal of Sports Medicine explains the athletic advantages of XY chromosomes at a cellular level. It shows that biological males have advantages in muscle mass, lean body mass, muscle strength, and two measurements of endurance (hemoglobin and hematocrit), plus the indirect measures of efficacy of oxygenation transportation and delivery. While synthetic estrogen and anti-testosterone pharmaceuticals have been shown to slightly decrease these parameters—and even if normal male testosterone levels are absent at the time of competition—inborn advantages from the latent effects of a lifetime of testosterone persist. The article concludes “values for strength, [lean body mass] and muscle area in transwomen remain above those of [biological] women, even after 36 months of hormone therapy.”

Testosterone exposure during puberty increases present and future exercise performance and muscle stamina, and muscle stamina is influenced by oxygen consumption. Males have physiologically wider airways due to testosterone exposure. According to researchers in the journal Breathe “The greater oxygen cost of breathing in women means that a greater fraction of total oxygen uptake and cardiac output is directed to the respiratory muscles, influencing exercise performance.”

The fairly obvious outward dimorphism between males and females are just some of the many physiologic and metabolic differences between sexes—which are exactly what sex-specific sports were designed to correct for.

If you thought athletes like UPenn swimmer Lia Thomas are something new, you would be mistaken. In fact, men trying to enter women’s sports is a decades-old phenomenon. Men trying to participate in women’s sports historically used to be refused well before they got anywhere near the point of competition.

Media reports exist at least as far back as the 1930s of men masquerading as women in order to participate in women’s sports and acquire ill-gotten fame. Because this problem has persisted over time, and in an attempt to prevent it, regulations governing the participation of athletes across the biological sex binary have existed since the 1940s.

Surreal progressive colleges, universities, and athletic organizations want to ignore biology and encourage the Kafkaesque. This trend denies America’s women fair competition for a chance at victories. While it appears a fleeting few professional organizations such as USA Cycling are finally beginning to figure it out, it’s nowhere near enough.

The scientific answer will always be to have both biological male and biological female sports.

David Gortler, Pharm.D. FCCP is a Fellow at the Ethics and Public Policy Center whose work focuses on FDA oversight and accountability. Dr. Gortler is a pharmacologist and pharmacist and a Yale-trained bench research scientist in molecular biology with a subspecialty in the field of vascular medicine.  He was a professor of pharmacology and biotechnology at the Yale University School of Medicine, where he also served at Yale’s Center for Bioethics, and was an FDA Medical Officer who was later appointed by the White House to serve on the FDA’s Senior Executive Leadership Team as senior advisor to the FDA Commissioner.

Photo by Serena Repice Lentini on Unsplash

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