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All athletes wishing to compete successful nan female class astatine nan World Championships are required to return nan test
Rules requiring each athletes successful nan female class of world ranking events to return a one-time cistron trial travel into unit this week.
World Athletics says nan activity screening - which detects nan beingness of a Y chromosome - is to protect nan integrity of women's competition.
But really does nan latest effort to tackle 1 of sport's astir contentious issues work? How did we get here, are location concerns, and what are nan implications for nan statement astir gender eligibility? BBC Sport answers nan cardinal questions.
What is nan trial looking for?
The trial detects nan SRY cistron - aliases 'sex-determining region Y gene' - which is portion of nan Y chromosome and causes antheral characteristics to develop.
If a quality embryo has XY chromosomes nan SRY cistron leads to nan statement of testes, which past nutrient hormones including testosterone that lead to antheral improvement - and tin summation musculus wide and strength.
Research has shown athletes who were calved antheral and passed done antheral puberty mostly person physiological advantages complete those calved female (with XX chromosomes and nary SRY gene).
The trial is designed to find biologic activity successful cases of athletes who are DSD - those calved pinch 'differences successful activity development'. This is simply a word for a group of uncommon conditions, whereby a person's hormones, genes and/or reproductive organs whitethorn beryllium a operation of antheral and female characteristics. Some tin beryllium calved pinch outer female genitalia but functioning testes, and are often certified arsenic female astatine commencement and raised arsenic such.
How will nan SRY trial beryllium conducted?
It is simply a feature swab aliases humor test, which is done erstwhile successful an athlete's life by each nationalist federation. If nan trial is antagonistic for nan Y chromosome - i.e. it is absent - nan jock is eligible to compete successful nan female category.
However, World Athletics says that a affirmative trial whitethorn hap if nan jock has nan DSD information 46 XY, and that "such individuals pinch typically antheral chromosomes whitethorn person atypical improvement of reproductive aliases intersexual anatomy owed to variations successful nan SRY cistron aliases different related familial factors", pinch immoderate assigned a female gender astatine birth.
In specified cases, unless nan jock has complete androgen insensitivity syndrome (CAIS) - and has not gone done antheral puberty - they would beryllium ineligible to compete successful nan female category.
World Athletics is besides allowing "a very mini number of known DSD athletes to compete nether nan existent regulations", arsenic agelong arsenic they proceed to comply.
How galore tests person been done?
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World Athletics president Lord Coe says athletes are "overwhelmingly supportive" astir nan cistron test
World Athletics says more than 90% of nan athletes owed to return portion successful nan World Championships later this period person been tested, pinch immoderate outstanding cases to beryllium conducted successful Tokyo.
Its president Lord Coe has admitted nan clip framework has been "tight", and that location has been "added complexity" because familial testing for non-medical reasons is outlawed successful immoderate countries, specified arsenic France and Norway, truthful immoderate athletes person had to springiness samples overseas.
A group of Canadian athletes besides had to beryllium retested aft a reported 'test-tube error' meant their feature swabs grounded to comply pinch requirements.
Why has World Athletics chosen to do this now?
Gender successful athletics has been a awesome rumor since 2009, erstwhile South African Caster Semenya won nan 800m last astatine nan World Championships successful Berlin - going connected to predominate astatine nan distance.
She was calved pinch 46 XY 5-ARD (5-alpha-reductase deficiency). People pinch this peculiar DSD person antheral XY chromosomes, but immoderate are recorded arsenic female astatine birth.
Semenya was legally registered arsenic female astatine commencement and has said that though she was calved without a uterus and pinch soul testicles, she has a pussy and is simply a woman.
At nan 2016 Olympics successful Rio, each 3 medallists successful nan women's 800m (including victor Semenya) were DSD athletes, intensifying calls for tighter rules. World Athletics past insisted that for way events from 400m up to nan mile, DSD athletes must trim their testosterone levels successful bid to beryllium eligible.
Semenya refused, arguing it was an infringement of her quality authorities and discriminatory.
Amid a agelong ineligible battle, World Athletics' made its rules stricter successful 2023. Transgender women who had gone done antheral puberty were banned from competing successful women's events, while DSD athletes had to further trim their testosterone levels and for longer, and successful each way and section events.
Then, earlier this year, a World Athletics moving group recommended going further still, claiming caller investigation showed testosterone suppression could only partially mitigate nan wide antheral advantage.
The governing assemblage said nan SRY cistron is "a reliable proxy for determining biologic sex" and that nan mostly of those it consulted supported a feature swab test.
"It is really important successful a athletics that is permanently trying to pull much women that they participate a athletics believing location is nary biologic solid ceiling," said Lord Coe astatine nan time.
"At elite level, for you to compete successful nan female class you person to beryllium biologically female."
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Gender successful athletics has been an rumor since Semenya's 800m World Championship occurrence successful 2009
What astir different sports?
World Boxing besides introduced mandatory activity testing this year, pinch immoderate fighters wanting to return portion successful nan female title astatine nan World Championships successful Liverpool this week having had to return a test.
"Athletes that are deemed to beryllium antheral astatine birth, arsenic evidenced by nan beingness of Y chromosome familial worldly (the SRY gene) aliases pinch a quality of intersexual improvement (DSD) wherever antheral androgenization occurs, will beryllium eligible to compete successful nan antheral category," nan governing assemblage said successful May.
This followed a awesome contention successful nan women's boxing title astatine nan 2024 Paris Olympics, wherever Imane Khelif and Lin Yu-ting some won golds contempt being disqualified from nan erstwhile year's World Championships for allegedly failing gender eligibility tests conducted by past governing assemblage nan IBA.
The IBA was past suspended and truthful nan International Olympic Committee (IOC) ran nan boxing title successful Paris and allowed nan fighters to compete, insisting they met eligibility requirements. This sparked scrutiny complete whether nan assemblage had put inclusion complete fairness and safety, and nan reliability of nan IBA's original tests.
Khelif and Yu-ting were assigned female astatine commencement and insist they are women. But nan IBA's declare that Khelif has XY chromosomes led to speculation nan combatant whitethorn person been calved pinch a DSD. The BBC has not been capable to corroborate whether this is nan case. It is besides not known whether Khelif and Yu-ting person taken nan SRY test, but neither is expected to compete astatine nan World Championships.
Will nan IOC adopt nan tests?
The IOC has been wary of activity screening for fearfulness of stigmatising aliases discriminating against athletes. In 2024, past president Thomas Bach besides said: "It is not arsenic easy arsenic immoderate whitethorn now want to represent it - that XX aliases XY is nan clear favoritism betwixt men and women. This is scientifically not existent immoderate more."
However, aft nan Paris 2024 boxing controversy, nan United Nations' typical rapporteur connected unit against women called for activity screening for female athletes, external to beryllium reintroduced. A group of 32 academics agreed,, external claiming it was "overwhelmingly preferable to targeted testing based connected allegations, suspicion and bias".
New IOC president Kirsty Coventry says protecting nan female class is simply a priority, and seems unfastened to applying specified a trial crossed each sports. Meanwhile, US President Donald Trump has said activity testing successful immoderate shape will beryllium applied for women's title astatine nan LA Olympics successful 2028.
However, Andrew Parsons, nan president of nan International Paralympic Committee, says he is opposed to "blanket solutions" to gender eligibility, suggesting each federation should still beryllium near to determine its ain rules.
Have gender tests been utilized before?
The IOC utilized ocular inspections successful nan 1960s, but location were concerns they were degrading and invasive, earlier mandatory chromosome-based feature swab tests were introduced.
There were still issues, however. Spanish hurdler Maria Jose Martinez Patino was barred from title successful 1986 aft failing nan test, but later examinations showed that while she had XY chromosomes she besides had CAIS - meaning her assemblage ne'er gained benefits from nan accrued testosterone created by her soul testes.
She was reinstated, but amid a number of 'false positives', and fears that female athletes were being punished for earthy variations, gender verification tests were abolished successful nan 1990s.
World Athletics insists nan caller tests are now "extremely meticulous and nan consequence of mendacious antagonistic aliases affirmative is highly unlikely".
What has been nan reaction?
Lord Coe says athletes person been "overwhelmingly supportive" of nan caller tests. Campaign group Sex Matters said nan return of screening was "welcome and overdue", adding: "Every athletics needs to travel nan lead of World Athletics and World Boxing."
However, US runner Nikki Hiltz - who is transgender and non-binary - said nan cistron testing was "disappointing", adding: "I conscionable don't for illustration nan precedent that it sets."
Hiltz - who has qualified for nan World Championships and has taken a trial - expressed concern, external it mightiness mean much invasive techniques are used, and that nan estimated $100 (£74) costs for each trial would beryllium amended spent tackling doping aliases abusive coaches.
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Hiltz was assigned female astatine commencement and came retired arsenic transgender and non-binary successful 2021
Within nan technological organization location is besides opposition. Andrew Sinclair, a professor of translational genomics astatine nan University of Melbourne - who discovered nan SRY cistron successful 1990 - precocious wrote that mandatory activity testing was "misguided"., external
He said that "using SRY to found biologic activity is incorrect because each it tells you is whether aliases not nan cistron is present," and that "the subject does not support this overly simplistic assertion". He besides raised concerns astir nan consequence of accidental contamination and a imaginable mendacious positive.
And Madeleine Pape, a erstwhile Australian Olympian and a sociologist astatine nan University of Lausanne, has besides raised concerns astir nan trial inadvertently 'outing' athletes - immoderate of whom whitethorn ne'er person known they had a DSD.
"It is acold from being scientifically meticulous arsenic a capacity indicator, while being very harmful to nan athletes affected," she said.
World Athletics says immoderate first affirmative results will beryllium followed up pinch further aesculapian assessments, allowing for an meticulous test earlier a determination complete eligibility is made. It says a healthcare master will besides talk nan results pinch an athlete, helping them understand immoderate medical, psychological aliases societal implications.
In position of privacy, athletes person been told they will upload their trial consequence connected a secure, encrypted platform, and that they tin petition a retest and situation results via nan Court of Arbitration for Sport (CAS).
Supporters besides opportunity this method is much humane than requiring DSD athletes to suppress their earthy testosterone levels, and will debar nan aggravated media scrutiny that immoderate athletes person been subjected to.
Could nan caller tests look ineligible challenges?
Some experts are predicting ineligible challenges, though Lord Coe says he's assured nan argumentation will guidelines up to immoderate - insisting world quality authorities standards are being respected.
Semenya has waged a agelong ineligible conflict against nan erstwhile activity eligibility rules. In 2019 she unsuccessfully challenged them astatine CAS. However, successful July nan European Court of Human Rights recovered her correct to a adjacent proceeding was violated by nan Swiss Federal Supreme Court erstwhile she mislaid a further entreaty successful 2020.
That partial triumph whitethorn mean renewed scrutiny connected regulations that immoderate sports opportunity are needed to protect fairness successful nan female category, but which critics reason are unethical and discriminatory.