As schools wrap up one calendar year and gear up for the next, state legislatures are grappling with the question of whether schools should segregate sports by biological sex or allow students to compete based on their gender identity. This issue has far-reaching implications both inside and outside the school walls.
Currently, 22 states (most recently, Missouri, just this month) have passed laws mandating that only those who are biologically female can participate in girls’ and women’s sports. However, states such as Connecticut are being sued for allowing biological males to compete against females, while states such as West Virginia and Idaho are facing lawsuits for protecting women and girls in sports. The ACLU is representing a young male student in West Virginia who wishes to compete in girls’ sports. The question remains: does this student have inherent biological advantages, even at a prepubescent age?
As an exercise physiologist, I focus on the biological factors that influence health and human performance. The nervous, muscular, cardiovascular, respiratory, endocrine, and other systems all play a role in how a person adapts to exercise and can ultimately determine how someone will perform in sports. However, one of the most critical factors that influence adaptations to training and performance in sports is sex, as it influences every system and cell in our body.
The anatomical and physiological differences between males and females give males athletic advantages when compared to similarly aged, gifted, and trained females, regardless of age. Records from USA Track & Field show that in the eight-and-under age group and the nine-to-ten-year-old age group, boys run faster, jump longer, and throw farther than similarly aged girls in every event. Evaluations of fitness testing from around the world in children as young as three years old show that boys perform better than girls of the same age on tests of throwing, muscular strength, muscular endurance, and aerobic fitness. Prepubertal sex-based differences are smaller than the differences after puberty but are still meaningful in competition.
Puberty magnifies the sex-based differences in performance, with teenage boys and adult men outperforming girls and women by 10–15 percent in running, 15–20 percent in jumping, and 30–60 percent in strength. None of this is due to better training, nutrition, coaching, or motivation. Males have inherent biological advantages, such as taller body height, more lean body mass, more muscle mass, greater muscle strength, larger hearts and lungs, higher maximal oxygen consumption, and stronger bones than similarly aged, gifted, and trained females.
Even after a male has undergone hormone therapy, research shows that, while those biological advantages decrease, they are still far more prominent than similarly aged and trained women. Men have 30–60 percent higher muscle strength than women, and undergoing testosterone suppression decreases that strength by only 0–9 percent — a far cry from an even playing field for even the strongest female athletes.
While some women may be taller or stronger or run faster than some men, the tallest women are shorter than the tallest men, the most muscular men have significantly more muscle mass than the most muscular women, the strongest men are much stronger than the strongest women, and the fastest men are much faster than the fastest women. When comparing similarly aged, gifted, and trained males and females, the males’ inherent biological advantages tip the playing field unalterably in their favor.
A person cannot determine a transgender identity through a blood test, CT scan, MRI, genetic screening, or any other standard or specialized laboratory test. Therefore, if a male identifies as a girl or woman, biological sex is still present, and it is reasonable to conclude that he still has inherent male athletic advantages. Based on information from four different scholarly review papers by four different groups of scholars; separate reviews conducted by World Rugby, FINA, World Athletics, and the Sports Councils of the United Kingdom; and 27 peer-reviewed primary-research papers from many different research groups around the world, the current evidence indicates that identifying as transgender — with or without the use of puberty blockers, testosterone suppression, and/or cross-sex hormones — does not erase the inherent male athletic advantages.
Many of these truths have been articulated in legal briefs and expert declarations filed in the lawsuits occurring around the country to protect women’s sports, including in one heard by the Second Circuit Court of Appeals on June 6, in which I myself submitted a declaration. My hope is that the judges who will decide these cases will fully consider the clear biological evidence in favor of fairness for women and girls in sports.
This statement is solely the opinion of the author and does not represent an official statement from the University of Nebraska at Kearney.
