Do Transgender Athletes Have an Unfair Advantage?
In sports reliant on explosive capacity (combat, weight lifting etc), post-HRT Trans Women retain a significant advantage over 46XX females.
HRT does not impact height, width, or limb length, has a very small impact on muscle fiber type, heart and lung size, and actually results in increased area bone mineral density. This would not mitigate advantages in explosive activities such as weight lifting, hammer throw etc.
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In endurance sports, Trans women may be sufficiently hindered by the process of HRT to equal but not exceed the capacity of 46XX females.
In a study in the Journal of Sporting Cultures and Identities, Trans Women undergoing HRT displayed hemoglobin, hematocrit, and low-density lipoprotein that resembled 46XX female values, as well as dramatically increased body fat levels, and reduced muscle mass.
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Hormone levels, specifically differences post-male puberty, are the main cause of the morphological advantage males have over females.
There is a strong link between hormone composition & athletic performance, above all testosterone levels. Pre-puberty, males have 03-2.4 nano-moles per litre (nmol/l). After it increases to between 9.2-31.8 nmol/l. Females remain in the 0.3-2.4 nmol/l range before & after puberty
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Within a year of taking high levels of testosterone, Trans Men displayed significant changes to factors involved in athletic performance.
Studies show Trans Men given 30 nmol/l testosterone for a year had increases of 20% thigh muscle mass, 19.2% overall muscle mass, 15% red blood cells. A study of 23 on cross-sex hormones for a year resulted in increases of 10.4% muscle mass, 18% grip strength, 9.7% body fat loss.
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Even within female athletes, higher levels of testosterone provide a significant performance advantage over females with lower levels.
A study looking at over 1,000 elite female athletes in 5 sports (400m, 400m hurdles, 800m, hammer throw, pole vault) showed that those with higher levels of natural testosterone (still rarely exceeding 2 nmol/l) had a 1.8% to 4.5% advantage in most (not all) track & field events.
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Studies show that Testosterone dramatically increases athletic performance capacity in post-menopausal women.
62 Post-menopausal women given 7.2 nmol/l of testosterone (similar to that of male puberty) exhibited a 4.4% increase in muscle mass, 3% in bloody haemoglobin, and 12-26% in muscle strength compared to a placebo group. This shows the significance of high levels of testosterone.
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Testosterone is not the sole factor at play when assessing athletic performance.
Hormones have a significant impact on height, width, and limb length during puberty. When hormones are taken as an adult post-puberty the impacts on these things is minimal to none as once our growth plates have fused, they stop growing.
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Pistorius was allowed to compete when the CAS panel determined he only had a significant advantage when running in a straight line.
Considering his disadvantage at the start of a race and in bends, there was not enough evidence of a net advantage. As such, it was not possible to prove that his use of running blades as a TUE took his overall net capacity above the 100% of a two-legged athlete.
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The concepts of Fair Use and Therapeutic Use Exemptions are key and have already precluded athletes from competition for an unfair advantage
Double leg amputee Oscar Pistorius was initially rejected from competing in the 2008 Olympics due to an advantage over athletes competing with two natural legs. Running at the same speed Pistorius was found to expend 25% less energy than able-bodied sprinters under study.
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TUEs allow athletes with a condition that causes them a deficit in performance to take prohibited substances to equalise their performance.
It is fine if a TUE takes an athlete up to 100% of the normal performance range, if above then it is not allowed. Even 1% makes a large difference in elite sports. In the 100m sprint, 0.7% was the difference between 1st and 2nd place in the 2016 Olympic final.
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Despite massive investment and increased participation in female sports, the athletic performance gender gap has barely changed since 1983.
The mean difference in performance is approximately 10%, ranging from 5.5% in Swimming, to 36.8% in Weight Lifting. Looking at top ten performers, analysis reveals a similar gender gap trend in 1982 at 11.7%. This suggests women will not run, jump, swim, or ride as fast as men.
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Humans are a sexually dimorphic species, this means that males and females typically exhibit significant differences.
Morphologically, size (height, width, limb length), muscle fiber composition, heart and lung size, hormonal composition etc, male and female humans typically fall within distinct ranges. These differences give most males an athletic advantage over most females.
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Sex is not as binary as once thought. Sexual organs, chromosomes (XX/XY), hormone levels heavily correlate with sex, but aren’t definitive.
Gamine type is a better decider: ie. a male will be capable of producing sperm gametes, having a Y chromosome, and be morphologically male. However those with Androgen Insensitivity Syndrome do not share all of these characteristics and can be easily mistaken for the opposite sex
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We currently categorise sports by sex due to the fact that most males have a significant morphological advantage over most females.
This is due to factors that heavily corrolate with the male sex and provide significant sporting performance advantages - height, width, heart and lung size, bone density, muscle mass, muscle fiber type, haemoglobin etc. Sports are segregated due to morphology, not chromosomes.
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Trans Men who transitioned after puberty do not have any athletic advantage compared to those born male who go through male puberty.
Trans Men prescribed male hormones after puberty have a TUE that puts them nowhere near 100% of male capacity. Those who take hormones before puberty have been shown to have performance levels comparable to 46XY men also prescribed testosterone-at or below the TUE 100% mark.
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Male puberty is the key factor determining athletic performance. Before the onset of puberty, performances in boys and girls are similar.
There are some small differences across sports, likely from physical and societal factors, but these are relatively minor. By the end of puberty, the differences between males and females are dramatic. 2,000 men in the world could beat the fastest ever female sprinter.
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Trans Women remain above normal performance levels accepted for TUEs for 46XX women even after prolonged periods on female hormones.
Trans Women who have undergone male puberty keep the physical advantages (height, width, limb length, heart & lung capacity etc) that result from the process. Evidence doesn’t currently suggest that hormone treatment sufficiently mitigates these advantages compared to 46XX women.
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Trans Women who underwent hormone therapy to transition before male puberty may not have the athletic advantages gained during this process.
A study conducted on autopsies of 113 bodies aged 1 week-20 years showed that before the age of 15 there was no difference between male and female muscles. Trans Women who transitioned before male puberty competing against 46XX women may be fairer than those who did so after.
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Even Trans Women who transition before male puberty could have an advantage over 46XX women.
46XY Male bodies contain more fast-twitch muscle fibers (between 18.6 and 68.5% depending on the types of twitch fibers) than 46XX females on average. It is unclear if this is mitigated by Trans Women not undergoing male puberty.