Sports and Sex

Why Females Deserve Their Own Space in Sports

By Greg Brown, PhD

Sex Is Not Gender Identity

Sex is an extremely important biological factor for the continuation of life for any species on earth. It is an indisputable biological fact that human reproduction requires the male gamete (a sperm) to unite with the female gamete (an egg) to propagate the human species. The anatomical and physiological organization of a human body around the production of either sperm or eggs results in a wide range of important sex related differences between human males (boys and men) and human females (girls and women).

Sex is an extremely important factor in terms of growth, development, and physical, mental, and emotional health. Certain disorders and diseases affect and manifest differently in males and females. While males are more likely to suffer a heart attack at a young age, females are more likely to suffer a fatal heart attack due to differences in how a heart attack manifests. Some disorders only affect men (e.g. testicular cancer) and some disorders only affect women (ovarian cancer, endometriosis). It is also well known that women have a higher lifetime prevalence of mood or anxiety disorders than men, while men are more likely to experience substance abuse or antisocial disorders. And yet in many countries, including Spain, Germany, Scotland, the United States of America, and others, there are efforts underway to redefine sex to mean gender identity. These efforts to replace sex with gender identity are often driven by support for transgender ideology and are couched in aspirations of inclusion and equity. But the goals of equity and inclusion for transgender people cannot supersede the cold hard reality that humans are either male or female based on biological factors.

Currently, there is no known biological cause for someone to have a gender identity that differs from their biological sex. Conducting an MRI, a CT Scan, or testing for hormone levels, genes, sex chromosomes, or any other typical or specialized biological or chemical test provides no insight into a person’s gender identity. In other words, a transgirl or transwoman is biologically male, and a transboy or transman is biologically female. And yet there is a movement to ignore biology in favor of the nebulous concept of gender identity in order to allow transgirls and transwomen to play sports in the female category. Ignoring the biological reality of a person’s sex in favor of their gender identity results in male bodied athletes having unfair advantages in female sports.

Even Before Puberty, Boys Have an Advantage

While sports for children before puberty are often focused on skill development and enjoyment and thus are often mixed sex, before puberty boys have strength, speed, and endurance advantages over similarly aged, gifted, and trained girls. The differences are on the order of 3-10%, which is smaller than those after puberty, but can still be seen when comparing top performing boys and girls. And these pre-pubescent male sports advantages are due to small but important innate sex-based anatomical and physiological differences.

Once puberty begins, it doesn’t require advanced education to observe that boys and men are bigger, faster, and stronger than similarly aged, gifted and trained girls and women. Anyone who pays attention can clearly see the sex-based differences in sports performance in middle and high school as boys get even bigger, faster, and stronger than similarly aged, trained, and gifted girls. Based on laboratory measured data and controlling for body weight, men have 40% more lower body strength and 60% more upper body strength than comparably aged, gifted, and trained women. Men typically have a 35% advantage in maximal oxygen consumption (which accounts for 30-40% of success in endurance sports). In other words, females that are in the top tier of physical fitness for women would be comparable to average or moderately trained men.

In terms of sports performance, after the onset of puberty, boys and men swim and run 10-13% faster, jump 16-22% higher or farther, serve a volleyball 29-34% faster, and can lift 30-60% more weight than similarly aged, trained, and gifted girls and women.  The differences in performance between males and females are so large that in a typical year several hundred high school aged boys run faster times than the current women’s world records. All of these male athletic advantages can be explained by male anatomy and physiology such as larger hearts and lungs, more lean body mass, larger muscle cells, higher bone mineral density, and other sex-based differences that arise simply from being male.

Despite these well-known male anatomical and physiological advantages, the International Olympic Committee, the NCAA, and many state scholastic sports associations have enacted policies that dictate the inclusion of transgender girls & women (who are biologically male) into girl’s and women’s sports. These decisions are based on the notion that a person’s gender identity is somehow more relevant than is their biological sex. These policies are also contrary to a growing body of research demonstrating that transwomen retain male anatomical and physiological benefits in lean body mass, muscle size, muscle strength, maximal oxygen consumption, and running speed even after years of testosterone suppression and cross sex hormone use.

Women Can’t Compete in “Women’s” Sports

To help put the male performance advantages into perspective, in a championship track race the difference between a gold and silver medal is typically ½ percent or less, and the difference between a gold medal and no medal is often less than 2 percent. Anabolic androgenic steroids, which are almost universally considered to be unfair and are banned in most sports, provide a 5-20% boost in strength. In the early 2000’s swimsuit companies developed so-called “supersuits” that improved swimming efficiency by 1-3%, and these “supsersuits” were deemed unfair and banned from use in competition. How then can a 10-60% athletic advantage due to male sex not be considered unfair in women’s sports?

Some people argue that allowing transwomen into women’s sports is not a big deal because there are only a few transwomen who are athletes. I would direct these people to the 2022 NCAA Division 1 Women’s swimming championship in which a single transwoman displaced at least two women from earning All-American status, won one national championship and went home with a fifth place trophy after finishing in a tie with a female (who was not even allowed to jointly hold the trophy for pictures), and displaced at least two other women by taking their places on the varsity squad of the school team. I would also direct these people to the 2020 Summer Games in which a 43-year-old transwoman displaced a 23-year-old indigenous female weightlifter from the opportunity to represent her country at the Olympic games. I would also point them to state of Connecticut in 2019 in which 2 transwomen won 15 women’s high school track championships that were once held by 9 different women. I can go on and on with examples of male bodied athletes displacing girls and women from female sports championships.  This begs the question of how many female athletes need to lose to transwomen for it to be wrong?

Nebraska Needs to Be Pro-Active

However, 18 states have passed laws stating that only those who are biologically female can compete in girl’s and women’s sports. Some of these laws have been enjoined (put on hold by a court injunction) while the laws in other states are in full effect. While there may not currently be an issue with transwomen competing in women’s sports in Nebraska, I think most Nebraskans can understand the importance of closing a gate before the cattle escape the pasture. I hope that legislators in Nebraska will take a stand to protect women’s sports and enact legislation stating that only those who are biologically female can compete in girl’s and women’s sports before one of our female athletes is displaced by a male bodied athlete who identifies as a woman.

Greg Brown, PhD is a Professor of Exercise Science, focusing on Exercise Physiology, at the University of Nebraska at Kearney.  These comments represent his own views and are not a statement on behalf of the University.