When the LPGA and the U.S. Golf Association revealed a new guideline that essentially bars transgender women from competing, they justified their decision by referencing medical specialists and studies suggesting that male puberty bestows an unfair competitive edge in the sport.

However, both organizations failed to provide specifics about the experts or the research backing their claims, and two specialists in transgender athlete studies indicated that no such research on golfers exists. Additionally, other experts point out that there is no solid evidence to support the idea that transgender women hold a competitive advantage.

“We found no substantial or reliable information in existing research that indicates an unfair advantage exists,” stated Debra Kriger, a research associate with E-Alliance, who was involved in analyzing the data concerning transgender women in sports for the Canadian Centre for Ethics in Sport.

In reality, most studies suggesting that transgender women excel in sports are based on comparisons with cisgender men, which is not a suitable measure. Other studies compare transgender women athletes to sedentary cisgender women, which is also inappropriate.

One of the few relevant studies that examined transgender women against cisgender women found that transgender women actually have lower lung capacity and cardiovascular performance, potentially putting them at a disadvantage.

“Transgender women athletes are quite different from cisgender male athletes,” noted Blair Hamilton, one of the study’s authors, published in April in the British Journal of Sports Medicine.

“This was a major takeaway from our research. They should be regarded as a distinct group for study purposes.”

The significant challenge is the limited number of transgender athletes, making comprehensive long-term studies difficult. Policies like those enacted by the LPGA and USGA further hinder research efforts, steering participation debates based on fear rather than evidence and understanding.

“The available data is quite limited,” said D.J. Oberlin, an assistant professor and exercise physiologist at Lehman College, who published a review of the science regarding transgender participation in sports last year.

Hamilton added, “As these policies continue to restrict access, the likelihood of uncovering accurate answers diminishes.”

According to a 2022 study by the Williams Institute, just 0.6 percent of Americans aged 13 and older identify as transgender. Despite some claims from politicians and conservative figures, the number of transgender athletes is even smaller.

NCAA president Charlie Baker reported last week that there are “fewer than 10” transgender athletes among 510,000 college athletes. Furthermore, there has only been one openly transgender woman in the Olympics since their inclusion in 2004, and no openly transgender women are present in the WNBA, NWSL, LPGA, or WTA.

However, transgender individuals, particularly athletes, are increasingly facing scrutiny from right-wing groups, which often rely on misinformation and negative rhetoric to marginalize them.

Opponents often label transgender women athletes as men, counter to research that indicates they are not. Even before beginning hormone therapy, transgender women display lower lean body mass and strength, a fact supported by the Canadian Centre for Ethics in Sport’s report from 2022. This trend appears to diminish further post-therapy, according to Kriger, who is now the assistant manager for Co-curricular, Equity, Diversity, Inclusion, and Belonging at the University of Toronto Faculty of Kinesiology and Physical Education.

Hamilton remarked, “Many advocates of these bans focus on the skeletal structure of transgender women, claiming they naturally possess greater muscle mass. However, when looking at transgender women athletes, they tend to be weaker and have less muscle mass compared to cisgender athletes.”

Additionally, the presumption surrounding the impact of previous testosterone exposure in transgender women is often incorrectly likened to doping effects, as outlined in the CCES report, which calls this a “false biological equivalency.” There’s also a tendency to predict the performance of transgender women based on that of cisgender men.

“Many assertions about testosterone’s advantages in athletics lack proper scrutiny, often being accepted without citation in biological research,” stated the CCES report.

When the International Women’s Forum, an organization critical of transgender women, sent a letter to officials at the Tour in August signed by 275 current and former players, they referenced performance stats of cisgender men to argue that cisgender women would suffer against transgender women competitors.

Neither the LPGA nor USGA clarified whether this letter influenced the development of their new gender policy, announced earlier this month. The LPGA stated that they consulted with “experts across a variety of fields, including medicine, science, sports physiology, golf performance, and gender policy law, alongside input from a diverse range of stakeholders.” The USGA mentioned it “sought insights from various experts in transgender medicine and sports science” and expressed assurance that they utilized unbiased, scientific research from independent experts.

However, Hamilton and Oberlin claim that no studies exist comparing the performance of transgender women golfers who have undergone gender-affirming hormone therapy with that of cisgender women golfers. With the LPGA and USGA withholding evidence to support their claims, it appears that their assumptions regarding transgender women are just that: mere assumptions.

“I believe they consulted some folks,” said Oberlin. “However, I’m not sure if they sought opinions broadly or just spoke to a small group of people who were likely to support their viewpoint.”

Kriger pointed out that the research team responsible for the CCES report was particularly struck by how unclear it is what truly grants any athlete a performance edge. Is it related to hormones, height, or perhaps limb length?

According to Kriger, it’s impossible to make broad statements about this. Not from a factual standpoint, at least.

“Understanding what drives peak performance is quite enigmatic,” she added. “Connecting that to certain biomarkers appears, based on the review, to be an ultimately fruitless endeavor. No definitive biomarker has emerged that can effectively differentiate gender or predict performance.”

“It seems,” she continued, “that the truth is likely a combination of factors.”

The restrictions on transgender athletes can be seen as a continuation of the long-standing efforts to regulate women’s bodies and their participation in sports. Women were prohibited from participating in the Boston Marathon until 1972 due to a belief that they were not “physiologically capable.” Women ski jumpers were barred from the Olympics until 2014 out of concern that their uteruses might fall out. In the 1960s, women were subjected to humiliating genital inspections, one notably referred to as “the nude parade” since it required athletes to walk past physicians without underwear. This practice was eventually replaced by genetic testing.

It took substantial scientific evidence to debunk these ridiculous beliefs, along with a dose of common sense, before they were abandoned. Who can say that the bans on transgender athletes won’t be viewed similarly in the future?

However, without further studies, ideally specific to individual sports, no definitive conclusions can be made. Until that happens, Hamilton along with the other contributors to the BJSM study warned sports organizations against instituting bans and excluding transgender athletes.

“If you’re so sure about your stance, why not let us conduct our research?” Hamilton suggested. “Allow transgender athletes to compete now, and let us evaluate them. If we find there’s an advantage, we will report our findings.”