The International Olympic Committee has defended its position as a second boxer who previously failed a gender eligibility test prepares to compete on Friday.
Taiwan's double world champion Lin Yu-ting is scheduled to compete on Friday at 2.30pm (UK time) against Sitora Turdibekova of Uzbekistan less than 24 hours after Algeria's Imane Khelif won her opening Olympic bout in just 46 seconds against Italian Angela Carini.
Lin lost her bronze medal at the 2023 World Championships after she failed to meet the International Boxing Association's (IBA) unspecified eligibility criteria. Khelif was also disqualified hours before her gold medal bout at the same competition.
However, the IBA was stripped of its status as the global governing body for boxing by the IOC in June last year because it failed to complete reforms on governance, finance and ethical issues. The IOC is running the boxing tournament in Paris and applying different eligibility criteria.
Khelif's victory on Thursday has turned those criteria into an international controversy, but the IOC has blamed the IBA for its "arbitrary" decision to disqualify Lin and Khelif last year.
"These two athletes were the victims of a sudden and arbitrary decision by the IBA," the IOC said in a statement.
"Towards the end of the IBA World Championships in 2023, they were suddenly disqualified without any due process.
"According to the IBA minutes available on their website, this decision was initially taken solely by the IBA Secretary General and CEO."
The IOC argued that the fighters have been competing in international boxing competitions for many years in the women's category, including the Tokyo Olympics which were held in 2021, and other World Championships and IBA-sanctioned tournaments.
"The current aggression against these two athletes is based entirely on this arbitrary decision, which was taken without any proper procedure especially considering that these athletes had been competing in top-level competition for many years," the statement continued.
"The IOC is saddened by the abuse that the two athletes are currently receiving. Every person has the right to practise sport without discrimination."
IOC spokesperson Mark Adams reiterated that position on Friday morning, saying: "The IOC is always trying to do a balance between inclusivity and fairness and that is a difficult one and something that we'll have to look at.
"That's an entirely separate question to what's going on here, which is when women boxers are being stigmatised and potentially forced out of competition."
The IBA had earlier criticised the IOC for its "inconsistencies in eligibility".
"Both Imane Khelif and Lin Yu-ting, post testing, did not meet the required eligibility criteria to compete within the female category of our respective events," said an IBA statement.
"The urgent nature of the decision (to disqualify the boxers) was justified, as the safety of our boxers is our top priority."
The statements came hours after Khelif defeated Carini in less than a minute, leaving the Italian in tears in the ring and reporting a suspected broken nose.
"It hurt so much. I am heartbroken," said Carini. "I was told a lot of times that I was a warrior, but I preferred to stop for my health. I have never felt a punch like this."
Italy's family minister Eugenia Roccella said on Wednesday: "It is surprising that there are no certain, strict, uniform criteria at the international level."
She added that it was strange "that there can be a suspicion, and far more than a suspicion, of an unfair and potentially dangerous contest for one of the contenders at the Olympics, an event that symbolises sporting fairness".
Algeria's Olympic committee (COA) has previously condemned the "baseless" attacks on Khelif.
What is a DSD?
Medical information is confidential, so we don't know for certain if the boxers at the heart of this controversy have DSD (differences in sex development).
But it is reasonable to believe that this is at the heart of the debate. It has caused controversy in sport before, most notably with the two-time Olympic 800m champion Caster Semenya.
The NHS defines DSD as "a group of rare conditions involving genes, hormones and reproductive organs, including genitals. It means a person's sex development is different to most other people's."
This means someone may have sex chromosomes usually associated with being male (XY chromosomes), but reproductive organs and genitals that may look different from usual.
Some people with DSDs are raised as a girl but have XY sex chromosomes, testosterone levels in the male range and the ability to use testosterone circulating within their bodies.
It is possible therefore that someone could be raised as a female but develop the advantages that going through male puberty gives an athlete.
In combat sports like boxing, many would regard this as a safety issue for those competing in the women's category. Others would argue that this goes against aims to achieve inclusivity in sport.
IBA rules prevent boxers with XY chromosomes from competing in women's events, but the IOC says inclusion should be the default criteria.
It is the IOC which has set the rules for boxing in Paris.
Analysis: Are Khelif and Lin medal contenders?
Sky Sports boxing expert John Dennen:
Khelif and Lin have been boxing on the international circuit for a number of years.
Khelif is a previous Olympian. She boxed at the Tokyo Games in 2021. She won her first bout there but came away without a medal after losing to Ireland's Kellie Harrington, the eventual champion, in the quarter-final.
She has become a top-level contender, reaching the final of the World Championships in 2022. Amy Broadhurst clearly outboxed her then to win the gold medal.
The following year at the World Championships in India she also reached the final. Notably she was permitted to box four times at that tournament before the IBA administered its gender eligibility test and disqualified her.
Khelif did not have a reputation as a power puncher on the amateur scene so it was all the more surprising to see her finish the Carini bout in under a minute.
Lin has an even longer track record in top-class amateur boxing. At the World Championships in 2016 she lost a tight bout to British star Nicola Adams. She's medalled at every Worlds afterwards until 2023 when she would have taken bronze until the IBA also disqualified her for failing a gender eligibility test. She too was permitted to box several times at that tournament before being expelled.
Lin has been highly effective at these major tournaments, but has traded wins and losses with other elite operators. In the last two years Brazil's Jucielen Cerqueira Romeu, Kazakhstan's Karina Ibragimova and Olympic champion Sena Irie have all beaten her.
Analysis: 'Issue is not going away from the Olympics'
Rob Harris, Sky News Sports Correspondent:
Thursday's fight blew into the open a debate – steps removed from sport's transgender inclusion discord – about the rights of an athlete to compete.
Does a potential strength advantage, with inherent dangers, outweigh the desire to be inclusive and non-discriminatory?
And at the heart of it all, Khelif, who just wants to fight. Whose attempts to console, comfort or reassure were rejected by the tearful rival who had been on the receiving end of those punches in the 46 seconds the bout lasted.
For days the very staging of this 66kg opening-round fight had been questioned but it also collided with a long-running dispute between the International Olympic Committee and the International Boxing Association.
Is it fair to fear being put in danger by someone far stronger in a combat sport?
Is it fair to exclude someone female at birth who has gone through no treatment to adjust testosterone levels that would gain a competitive advantage?
Mark Adams, of the IOC, said: "This involves real people and we're talking about real people's lives here.
"They have competed and they continue to compete in the women's competition. They have lost and they've won against other women throughout, over the years.
"And by the way, this isn't – we should make this absolutely clear for everyone – this is not a transgender issue."
But the issue is not going away from the Olympics however much its leadership is asking everyone to "dial it down".
Read Rob's analysis in full on the Sky News website