Democratic Rep. Ilhan Omar said in a letter to USA Powerlifting that it is a “myth” that trans women, individuals who were born as biological males who now identify as women, have a “direct competitive advantage” in the sport.

I have requested an investigation into @USAPowerlifting‘s discrimination against a member of the Minnesota trans community. Respect for human rights includes protections for our trans brothers and sisters. pic.twitter.com/3ou4FsSozA — Rep. Ilhan Omar (@Ilhan) February 5, 2019

“I urge you to reconsider this discriminatory, unscientific policy and follow the example of the International Olympic Committee. The myth that trans women have a ‘direct competitive advantage’ is not supported by medical science, and it continues to stoke fear and violence against one of the most at-risk committees in the world,” Omar said.

Verdict: False

There has not been a lot of scientific research on trans athletes in sports, but the view that trans women have a competitive advantage in powerlifting is not a “myth” or “unscientific.”

Trans women who undergo hormone therapy lower their testosterone levels, which studies suggest decreases athletic performance. But trans women may still have more strength than biological women pound for pound, and muscle memory may also provide an advantage.

Fact Check:

Omar sent the letter after USA Powerlifting denied transgender athlete JayCee Cooper’s application to compete at a Minnesota event in the women’s division.

“Male-to-female transgenders are not allowed to compete as females in our static strength sports as it is a direct competitive advantage,” a USA Powerlifting official told Cooper via email, Outsports reported. “Transgender male to female individuals having gone through male puberty confer an unfair competitive advantage over non-transgender females due to increased bone density and muscle mass from pubertal exposure to testosterone.”

Cooper later won a Minnesota state championship in the women’s division of a different group, the U.S. Powerlifting Association (USPA).

Omar’s letter cited a review of the literature on transgender participation in sports and transgender sports policies. “Currently, there is no direct or consistent research suggesting transgender female individuals (or male individuals) have an athletic advantage at any stage of their transition,” the review said.

Most of the research papers that the review examined, however, were qualitative in nature, interviewing transgender individuals about their experiences in sports, as opposed to experimental studies that assess whether transgender athletes have a competitive advantage.

Men have much higher average levels of testosterone, a hormone that helps build muscle mass and strength, than women. One 2010 study of world records found that since 1983, men in the Olympics performed about 10 percent better than women, with exact percentages varying from sport to sport. The gender gap in weightlifting world records was 36.8 percent, it found.

Because of this biological difference, some sports leagues allow trans women to compete if they meet certain hormonal levels, among other criteria. The International Olympic Committee (IOC) allows trans women in women’s sporting events if they have demonstrated levels of testosterone below 10 nmol/L for at least 12 months, remain below those levels for competition and don’t change their gender identity for at least four years.

Trans women who have not undergone hormone therapy, generally speaking, would be expected to have a physical competitive advantage.

“The day after a man decided to transition, the individual will have male sporting attributes and so, with all other things being equal will outperform” a biological woman, Richard Holt, a professor of diabetes and endocrinology at the University of Southampton, told The Daily Caller News Foundation in an email.

Some sporting leagues, including Canada’s university sports brand, allow trans women to compete in women’s sports without any hormone therapy requirement.

The larger question is whether trans women who have undergone hormone therapy still have a competitive advantage.

The review that Omar cited only looked at one experimental study that helps establish whether transgender individuals taking hormones can fairly compete in sports: a 2004 study that found that male-to-female transgender individuals’ levels of testosterone had decreased to biological women’s levels after one year of hormone therapy, using female-to-male (F-M) pre-hormone samples for comparison.

Muscle mass also decreased. However, it “remained significantly greater” than F-M muscle mass before transition, on average.

Factors other than testosterone may also impact performance.

“The physiological attributes of males that makes them naturally stronger including anatomical and biological features such as size, muscle mass, lung capacity, and heart size would be an advantage,” Alison Heather, a physiology professor at the University of Otago in New Zealand, told a New Zealand website. “Whether this normalizing of hormone levels (and at 10 NMOL/L it is debatable whether they are normalized enough) removes the vast majority of the advantage of having been male is still an unanswered question.”

USA Powerlifting raised the point that trans women have a higher bone density than biological women. Several studies have found that bone mineral density was preserved or increased in trans women after hormone therapy. Some other studies, though, said that low bone mass is not uncommon in trans women, that trans women had lower bone density than a group of control men and that a substantial number of trans women suffered from osteoporosis after hormone therapy.

A 2016 article published by the American College of Sports Medicine noted that “research into the advantage that transgender women possess in athletics is sparse,” but there have been a few key studies in addition to the 2004 paper that shed light on the matter.

One study on distance running from Joanna Harper, a medical physicist at Providence Portland Medical Center in Oregon, examined race times for eight trans women before and after hormonal transition. All runners except one, who started training more after transitioning to female, ran much slower in female races than in male races, but part of that could be due to age.

After being statistically adjusted to account for age and gender differences, the results make it “possible to state that transgender women run distance races at approximately the same level, for their respective gender, both before and after gender transition,” the study said. In other words, while the runners had slower times in the female races, they were about the same performance-wise compared to women as they were in male races compared to men.

In another analysis of four trans women in racing events, Harper found that their age-graded performance decreased after transitioning.

Critics argue, however, that the sample sizes are too small to be conclusive and rely too much on self-reported information.

Harper, a trans woman and athlete who helped craft the IOC rules on transgender athlete participation, told TheDCNF that transgender women have some advantages, and disadvantages, in certain sports.

“Even after hormone therapy, transgender women on average are taller, bigger and stronger, which are advantages in many sports,” Harper said. “It’s also true that transgender women have some disadvantages.”

For instance, a trans woman’s frame size does not change after hormone therapy, but muscle mass and aerobic capacity declines. “It’s like a big car with a small engine competing against a small car with a small engine,” Harper said.

As it relates to Omar’s claim – that trans athletes having a “direct competitive advantage” in powerlifting is a myth – Harper said that Omar’s statement is not factually accurate.

“You really want to look at it carefully, you want to be sport-specific,” Harper cautioned. “Weightlifting is divided by weight categories. Transgender women are certainly not taller or bigger than women in their weight category – they’re the same size. Are transgender women stronger pound for pound? … We don’t know for sure. It’s possible, it’s possible it’s not.”

Trans women would be overrepresented in sports if they were substantially advantaged, Harper argued. The percentage of left-handed Major League Baseball players, for example, is larger than the percentage of left-handed people in the general population – an indirect measure of their advantage in the sport. By contrast, there were nearly 219,000 women who participated in NCAA sports in 2017-2018, but Harper could only think of three trans women competing at that level, despite expecting the number to be around 1,000 statistically. Sociological factors, though, also affect trans participation in sports.

The important question, Harper said, is whether trans women and biological women can compete against one another in an “equitable and meaningful fashion.”

Issues may arise when trans women compete in a top-to-unlimited powerlifting bodyweight class. Cooper won the USPA competition in Minnesota while competing in the women’s top bodyweight class, 90.1 kilograms and up. Cooper, weighing 127.3 kilograms, would also be in the top women’s bodyweight class for USA Powerlifting, 84 kilograms and up, if allowed to compete.

Cooper only started competing in powerlifting about a year ago, according to one interview, but had been weightlifting for a while before that. Fair Play For Women, a U.K.-based group that opposes policies that allow trans individuals to participate in women’s sports, suggested in a tweet that Cooper’s quick success in the sport shows unfairness.

This is Minnesota Women’s Powerlifting State Champion. Jaycee set a new state record in women’s bench and won best overall lifter. Jaycee was born male and took up weightlifting about a year ago and now dominates the state female rankings. Think About It. https://t.co/fGnTuUghHF pic.twitter.com/EJ9rLeceFT — FairPlayForWomen (@fairplaywomen) February 10, 2019

Harper believes that Cooper isn’t a real threat to elite women’s powerlifting. “If you look at her particular weight category there is at least one American woman who is lifting twice as much as JayCee is,” Harper said. “So while JayCee won some very low-level competition, she’s no threat to be the best in the country by any stretch of the imagination.”

Cooper lifted a combined 854.3 pounds at the state competition between the squat, deadlift and bench press. Many biological women in lower weight classes far exceeded Cooper’s lifts at national competitions.

A large unresolved biological issue of trans participation in women’s sports is muscle memory. Fair Play For Women highlights this point. Nicola Williams, the group’s director, told TheDCNF in an email that trans women have a “performance advantage gained by a lifetime of growing, developing a training” on a male body.

Several studies find that skeletal muscle can “remember” earlier muscle growth – which is aided by testosterone.

“If an elite athlete takes performance-enhancing drugs to put on muscle bulk, their muscle may retain a memory of this prior muscle growth. If the athlete is caught and given a ban – it may be the case that short bans are not adequate, as they may continue to be at an advantage over their competitors because they have taken drugs earlier in life, despite not taking drugs anymore,” Robert Seaborne, co-author of one of the studies and then-PhD student at Keele University, said in a statement last year.

The 2016 article published by the American College of Sports Medicine said that more research is needed on muscle memory and whether hormone therapy has an effect on the number of myonuclei, which dictates training response, in trans women. “If not, some of the biological advantage of a male biology will remain, irrespective of ‘normalizing’ the levels of circulating hormones,” it said.

Heather, the physiology professor in New Zealand, expressed a similar sentiment. “Given the lack of research, there is a real need to study what physical advantages transgender females carry after hormone therapy with consideration required for different sports, trainability and for performance,” she said.

Fair Play For Women also argues that the IOC testosterone threshold of 10 nmol/L is too high. One study found that F-M transgender persons had average testosterone levels of 1.6 nmol/L prior to transition. Testosterone levels for trans women were 1 nmol/L a year after transition.

The IOC is reportedly considering lowering the testosterone threshold to 5 nmol/L.

The International Association of Athletics Federations in 2018 issued new caps of 5 nmol/L on testosterone levels for women competing in track races from 400m up to the mile. The new rules mean that Olympic 800m champion Caster Semenya of South Africa, widely thought to be intersex (born with both male and female biological features), may have to take medication that reduces testosterone levels, or otherwise be deemed ineligible. The rule is being challenged and not yet in effect.

Fair Play For Women advocates for converting male categories to “open” categories where any athlete can compete regardless of sex, gender identity or hormone levels. “Although some unfairness still inevitably remains in this solution, it is significantly less than the unfairness under the current rules and the impact on a very large and already disadvantaged group within sports; females,” its website says.

Omar’s office did not respond to a request for comment.

Follow Emily on Twitter

Have a fact check suggestion? Send ideas to [email protected]

Content created by The Daily Caller News Foundation is available without charge to any eligible news publisher that can provide a large audience. For licensing opportunities of our original content, please contact [email protected].