Editor's note: This is the portion of a bid highlighting the 2021 Olympic Games with a circumstantial accent connected wellness and wellness.
July 15, 2021 -- The information of transgender women successful pistillate sports volition garner adjacent much attraction erstwhile the New Zealand weightlifter, Laurel Hubbard, becomes the archetypal openly trans jock to enactment successful the Olympic games.
WebMD/Medscape interviewed sports physicist Joanna Harper, who has advised the International Olympic Committee (IOC) and different sporting bodies connected sex and sports. She pivoted from moving successful crab probe to becoming a PhD pupil astatine Loughborough University successful London, 1 of the world’s apical institutes for sports research, aft publishing connected contention times of nonelite athletes -- including herself -- earlier and aft transition.
This interrogation has been edited for magnitude and clarity.
This interrogation focuses connected transgender athletes – chiefly those assigned antheral astatine commencement who hormonally modulation to female. It does not code athletes, specified arsenic Caster Semenya, who person disorders of intersexual development.
Most guidelines connected the information of transgender women successful sports usage testosterone levels successful the anterior 12 months with cutoffs of 5 nanomoles per liter oregon 10 nanomoles per liter. Is that correct?
Harper: In 2016, the IOC adopted a line where trans women could vie aft 1 twelvemonth of having testosterone levels beneath 10 nanomoles per liter. World athletics subsequently enactment successful a regularisation that required 5 nanomoles per liter. But it's important to enactment that determination are antithetic tests utilized for those 2 rules.
The IOC regularisation is based connected immunoassay testing, and satellite athletics was based connected liquid chromatography wide spectrometry, oregon LCMS, for short. Basically, the 10 nanomoles connected an immunoassay is equivalent to astir 7.5 nanomoles by LCMS. The thought that satellite athletics has fractional the testosterone bounds is perfectly not true, due to the fact that you're talking astir antithetic investigating methodologies.
The NCAA does not really person a testosterone limit; they require 1 twelvemonth of hormone therapy, but there's nary testosterone bounds with that. And there's small to nary testosterone investigating done by the NCAA.
Testosterone levels driblet rapidly aft hormone treatment. Is it existent that the testosterone levels of trans women are akin to cis pistillate levels?
Harper: Absolutely. 95% of cisgender women person testosterone beneath 2 nanomoles per liter. And successful a recent survey of astir 250 trans women, 94% of them had testosterone beneath 2 nanomoles per liter.
It doesn't truly substance whether the bounds is 5 oregon 10 nanomoles per liter due to the fact that astir trans women are going to beryllium nether 2 anyway.
Hemoglobin levels are higher successful men, which allows much oxygen to get into the muscles. Is the main vantage of that greater endurance due to the fact that muscles don't fatigue arsenic quickly?
Harper: Yes, the azygous astir important physiological origin for endurance athletes is hemoglobin. In sports it’s often measured arsenic hematocrit levels. Hematocrit is the percent of humor that's reddish humor cells.
That's the crushed that endurance athletes spell to altitude to train, oregon [those who cheat] usage humor doping oregon EPO. There are a batch of things that spell into making an endurance athlete, but the azygous astir important origin would beryllium hemoglobin levels.
Hemoglobin levels besides driblet arsenic testosterone levels decline, right?
Harper: Hemoglobin levels travel the testosterone. Within weeks of starting testosterone suppression, testosterone levels volition beryllium wrong pistillate norms, but it takes a small longer for hemoglobin to get the pistillate norms, astir apt successful the 3- to 4-month range. That's astir the beingness rhythm of reddish humor cells.
As trans women regenerate their reddish humor cells, with their caller little testosterone levels, they volition person less reddish humor cells and little hemoglobin, but it does instrumentality 3 to 4 months.
What distances are we typically talking astir wherever endurance is an vantage -- is it an 800-meter way event, oregon is it much successful the 1,500 meters and supra range?
Harper: The 800 meters is apt much velocity than endurance. You're astir apt talking 1,500 meters and above, but that’s conscionable track. There’s [also] region swimming, region cycling, the triathlon. There are immoderate fig of endurance benignant sports.
How are different imaginable advantages specified arsenic thin assemblage wide and spot affected by aesculapian transition?
Harper: Lean assemblage wide and spot are little affected than hemoglobin, but we don't truly person studies connected trans athletes. Our review and another 1 looked astatine studies connected non-athletes. One of the important things to enactment is that adjacent earlier starting hormone therapy, the trans women successful these studies were substantially little beardown than cis men. I enactment it colloquially that arsenic a colonisation group, trans women would alternatively starve themselves to look similar models, than enactment connected musculus to beryllium athletes.
But that's the colonisation these studies looked astatine -- they weren't looking astatine trans women who are progressive successful sports. We recovered that the trans women didn't suffer precise overmuch spot oregon thin assemblage mass. But they astir apt didn't physique up precise overmuch earlier they started hormone therapy. How applicable that uncovering is to trans athletes is somewhat debatable.
There's perfectly nary question successful my caput that trans women volition support spot advantages implicit cis women, adjacent aft hormone therapy. That's based connected my objective experience, alternatively than published data, but I would accidental there's zero uncertainty successful my mind.
Your reappraisal recovered that thin assemblage wide and musculus spot diminution but stay supra cis pistillate levels up to 3 years aft hormone transition. Do you deliberation that represents a plateau oregon that determination volition beryllium further declines implicit time?
Harper: It is astir apt existent that the top changes successful the spot of trans women connected hormone therapy hap successful the archetypal 12 months, but determination aren't capable information to marque a definitive statement. It is imaginable that determination are further declines successful spot aft 36 months, and a caller tiny study retired of Brazil suggests that the full spot vantage mightiness spell away. But they conscionable looked astatine grip spot successful 8 trans women, compared with 8 cis women matched for BMI, truthful I deliberation the substance is acold from settled.
A caller insubstantial quantified the antheral vantage crossed assorted sports utilizing information from cis men and women. Track and swimming were astatine the little extremity with astir a 12% differential, weightlifting was connected the precocious end, and for throwing a shot transportation that was a 50% difference. Do you deliberation these comparisons are valid?
Harper: I don't quality their information connected cis radical astatine all. I deliberation that they did a bully occupation compiling that.
Given the range, would you presume that determination mightiness beryllium antithetic advantages for trans women successful antithetic sports?
Harper: Absolutely. I've been saying since 2018 that we should beryllium looking sport-by-sport connected regulations for trans athletes.
The spot differences betwixt cis men and women are higher for precocious assemblage spot than little body, truthful tin we presume that trans women volition person much of an vantage successful sports that necessitate much precocious assemblage strength?
Harper: It’s not conscionable strength, it’s tallness sports. Trans pistillate volition suffer spot with aesculapian transition, but they won’t suffer tallness astatine all. In sports, similar hoops and volleyball, that vantage isn't going to beryllium mitigated; the spot vantage volition beryllium mitigated, but that the tallness vantage isn't going to spell distant astatine all.
So far, we’ve been talking astir trans women who transitioned aft puberty. Presumably, determination is nary vantage if a trans miss ne'er went done antheral puberty?
Harper: I fishy that trans girls would still, connected average, beryllium taller. I don't cognize that for certain. There whitethorn beryllium precise minimal advantages. When the IOC archetypal enactment rules successful spot successful 2004, they said these rules lone use to trans women who acquisition antheral puberty.
So, the IOC has agelong said that immoderate advantages that trans women who don't spell done antheral puberty are tiny capable that they're not going to interest astir it. Most sporting organizations would accidental the aforesaid thing. Not everyone would agree, but astir sporting bodies hold connected that.
For trans women’s information successful pistillate sports, is your extremity to alteration just competition?
Harper: I similar to usage the word “meaningful competition.” We ever absorption connected advantages; good we really let advantages successful sport. And we let advantages for 1 radical implicit another. For instance, successful baseball, the configuration of the diamond lends galore advantages to left-handed players over right-handed players. And yet, that's an vantage we allow.
On the different hand, we don’t fto heavyweight boxers get into the ringing with flyweight boxers. And here's the important difference. We tin person meaningful contention betwixt left-handed shot players, and right-handed shot players, contempt the advantages. In fact, galore would accidental that the lefty/righty operation is 1 of the astir important factors successful baseball. But there's nary meaningful contention betwixt large boxers and small boxers; the large boxer wins each time.
The important question isn't, “Do trans women person advantages?” What truly matters is tin trans women and cis women vie against 1 different successful meaningful competition. There's nary denotation that trans women are anyplace adjacent to taking implicit women's sport, it's not happening now. It's not apt to hap anytime successful the future.
Boxing brings up interaction and collision sports. World Rugby precocious came retired against trans women's participation successful women’s rugby, citing information issues.
Harper: I perfectly hold that there's a information contented due to the fact that connected average, trans women are taller and bigger than cis women. If you're looking astatine collision metrics, the 2 important factors are size and speed. The data I gathered from 20 region runners and sprinters suggests that trans women aren't faster than cis women. A study from the U.S. Air Force does suggest that trans women are faster, but [it] didn't measurement grooming successful immoderate way. They are inactive going to beryllium bigger than cis women.
Now, of course, what you truly privation to cognize is however large are the trans women playing rugby versus the cis women playing rugby? We don't person immoderate information connected that. But arsenic a colonisation group, trans women are bigger than cis women, truthful there's decidedly immoderate crushed for interest implicit a imaginable information issue.
But you would similar inclusion, and you deliberation that the information contented could beryllium navigated?
Harper: I don't deliberation that banning trans women is the close approach. World Rugby calculated a 20% to 30% accrued hazard erstwhile a shot bearer of emblematic pistillate wide was tackled by a shot bearer of emblematic antheral mass. But, arsenic I said earlier, if you look astatine the studies of non-athletic trans women, trans women don't person emblematic antheral assemblage mass. Trans women are nary much than halfway betwixt pistillate wide and antheral wide and possibly adjacent person to emblematic pistillate mass.
The question is: How large are the women playing rugby? We don't cognize that. We've applied for a assistance from World Rugby to survey that question. Hopefully, they'll cough up immoderate wealth due to the fact that that's the important question.
By the way, World Rugby lone looks astatine international-level rugby, and nary openly trans pistillate has ever played an planetary rugby match. So, the full hazard summation from trans women successful planetary rugby is zero truthful acold due to the fact that determination are nary trans women. That whitethorn alteration -- there's a trans pistillate successful France who mightiness someday marque the nationalist squad -- but that's a precise tiny number.
I suggested to World Rugby that they enactment a bounds connected each nationalist squad of 1 trans pistillate per team. Because adjacent if determination was a 20% hazard increase, erstwhile a trans pistillate tackles a cis woman, and I'm rather certain, it's not that big, if lone 1 of 15 players connected the tract was trans, past lone a precise tiny percent of the tackles would beryllium made by a trans woman. In a fixed match, you're looking astatine a precise tiny summation successful risk.
That was my proposition to World Rugby, but they didn't instrumentality it. No trans women are presently banned from rugby, due to the fact that arsenic it stands close present successful the planetary game, determination are nary bully enough. We'll spot what develops successful the future.
Are determination immoderate imaginable disadvantages for trans women athletes?
Harper: Absolutely. Trans women person larger frames, which are present being powered by reduced musculus wide and reduced aerobic capacity, and that tin pb to disadvantages successful things similar quickness, betterment endurance, and things that mightiness not beryllium rather arsenic evident arsenic seeing idiosyncratic bigger.
How bash these disadvantages play out? We don’t cognize yet due to the fact that the probe is precise aboriginal on. But the thought that trans women lone person advantages conscionable isn't true. The analogy I've utilized is that it's similar a large car with a tiny motor competing against a tiny car with a tiny engine.
With trans men, is the presumption that there's nary advantage?
Harper: Trans men are allowed to inject testosterone and nary different athletes are allowed to bash that. It's unclear close now, but adjacent aft taking testosterone, trans men are going to beryllium shorter, they're going to beryllium lighter, and they're astir apt not going to scope emblematic antheral strength. Those are reasonably important disadvantages.
The study from the U.S. Air Force that I mentioned earlier looked astatine trans men and trans women successful 3 fitness tests earlier and aft their transition. The tests were a 1.5-mile tally and the fig of situps and pushups that tin beryllium done successful a minute. After 2 years of hormone therapy, the trans men matched the cis men successful the 1.5-mile tally and successful the fig of pushups per minute, and they exceeded the cis men successful the fig of situps per minute. There whitethorn beryllium immoderate advantages that trans men person successful sports, we’ll person to spot however that each plays out. I'm inclined to deliberation that trans men are little apt to beryllium palmy successful men's sports than trans women are successful women's sports.
There are immoderate sports wherever you get subdivided by weight, and past the information that trans men are smaller is not truly a disadvantage, due to the fact that you're usually the aforesaid size arsenic idiosyncratic successful your value class. Those whitethorn beryllium the sports wherever trans men person greater success. But again, it's precise aboriginal days.
Do we cognize if there's immoderate quality (assuming they've gone done antheral puberty) if a trans pistillate transitioned astatine accidental 21 versus 31 years of age?
Harper: I'm not definite there's a quality betwixt 21 and 31. There's surely a quality betwixt 11 and 21. I would deliberation that immoderate further testosterone gains from 21 to 31 that mightiness not beryllium undone by hormone therapy would beryllium precise small.
This is simply a precise divisive topic, but you look to beryllium little dogmatic than immoderate of the radical connected either broadside of this issue. Is that a just practice of your constituent of view?
Harper: I person been reviled by radical connected either broadside of the chasm. I effort to travel the data. I effort to usage logic and crushed and rational thinking. I besides effort to speech astir these things calmly -- arsenic you astir apt noticed, that is somewhat successful abbreviated supply. I whitethorn beryllium 1 of the fewer to bash that, but I'm surely not the lone one.
Most radical that I've travel crossed done the planetary sporting bodies privation to navigate the somewhat treacherous mediate crushed successful these debates.
You've worked with groups from some sides of the debate. How bash you marque a favoritism betwixt a radical similar the Women’s Sports Policy Working Group , that look to beryllium ‘good religion actors’, if I tin usage that term, versus those utilizing fairness for women's sports arsenic a fig leafage of respectability for a broader anti-trans agenda?
Harper: A fig of states that person introduced bills to prohibition trans women successful sports person said they're trying to prevention women’s sports. But successful summation to these bans, they're besides introducing authorities to effort to bounds the lives of trans radical successful different ways. They're showing their existent colors.
The radical who founded this Women's Sports Policy Working Group genuinely bash attraction astir women’s sports. People similar Donna de Varona, Martina Navratilova, Nancy Hogshead-Makar, and Doriane Coleman person achieved connected the sporting tract and successful beingness successful general, and they attraction precise overmuch astir women's sport. So, there's a immense chasm betwixt these 2 groups.