Boxing is suddenly in the middle of a scandal at the Paris Olympics after a pair of fighters — Algeria's Imane Khelif and Chinese Taipei's Lin Yu-ting — started competing at the Games despite failing unspecified gender eligibility tests in 2023.

Here’s a look back and how Khelif and Yu-ting got here and what led up to the controversy this week in Paris:

June 2019: IOC suspends IBA as governing body

The International Olympic Committee and the International Boxing Association have been in a feud for years. The IOC first suspended the IBA as the sport’s governing body for the Games in 2019 over what it saw were several issues with the organization, including its financial status, the integrity of fights and judges and its leadership.

This decision allowed the IOC to move forward without the IBA for the 2021 Tokyo Olympics.

July 2021: Khelif, Yu-ting compete in Tokyo Olympics

Both Khelif and Yu-ting competed at the Tokyo Olympics without any issues.

Khelif reached the women's lightweight quarterfinals, and Yu-ting was eliminated in the round of 16 in the women’s featherweight division. The IOC governed the Olympic sport at this time.

2022, early 2023: Khelif, Yu-ting have strong performances

Both Khelif and Yu-ting had very impressive runs in both 2022 and early 2023. Khelif won gold at the Africa Championships in 2022 and then fell in the gold medal match at the world championships to Ireland’s Amy Broadhurst.

Yu-ting won gold in the women’s featherweight division at the 2022 world championships when she beat Irma Testa in the final match. She also won gold at the Asian Games the following year.

March 2023: IBA disqualifies Khelif, Yu-ting for failing gender eligibility tests

After first conducting unspecified gender eligibility tests in 2022 and again at the world championships in New Delhi in 2023, the IBA suddenly disqualified both Khelif and Yu-ting from competition after it claimed the two athletes failed. Evidence of the alleged failed tests remain confidential, but the IBA rules prevent athletes with XY chromosomes from competing in women’s events.

Most men are born with one X and one Y chromosome, and most women are born with two X chromosomes, however there are plenty of exceptions and they are not the only determining factor for someones sex.

Yu-ting was stripped of her bronze medal after the IBA claimed she failed to meet unspecified eligibility requirements in a biochemical test, and Khelif was disqualified for what the IBA claimed were elevated levels of testosterone just hours before her gold medal fight.

The IBA said this week that those decisions were made “after a meticulous review.” The IOC said this was a “sudden and arbitrary decision” that was made “without any due process.” It’s unclear what specifically went into these gender eligibility tests.

June 2023/April 2024: IOC stops recognizing IBA as governing body

The IOC stopped recognizing the IBA as the sport's governing body in 2023, a move which was upheld by the Court of Arbitration for Sport in April 2024. It first suspended the IBA in 2019. The IBA was dropped due to a lack of financial transparency and sustainability, its refereeing and judges policies and more.

The Paris 2024 Boxing Unit is now in charge of competition. According to the IOC, as it has been with past boxing competitions at the Games, “the gender and age of the athletes are based on their passport.”

Aug. 1: Italy’s Angela Carini stops fight against Algeria’s Imane Khelif

Angela Carini retired from her fight against Algeria's Imane Khelif less than a minute in on Thursday in Paris after taking a series of hard punches in the opening seconds of the bout.

"I had entered the ring to fight," Carini said in Italian after the fight. "I didn't give up, but a punch hurt too much and so I said enough. I go out with my head held high."

Khelif did not speak to reporters after the fight. Algeria’s Olympic committee issued a strong statement the day before slamming the “unethical targeting and maligning” of her by foreign media outlets, which it called “deeply unfair.”

Aug. 1: IOC condemns ‘attacks’ against boxers in statement

The IOC defended both Khelif and Yu-ting in a lengthy statement on Thursday night, and said that "every person has the right to practice sport without discrimination." The organization also condemned the harsh attacks that came against the two athletes on social media, and said it was "saddened by the abuse that the two athletes are currently receiving."

The IOC laid out a long defense of both athletes in its statement, saying that both “have been competing in international boxing competitions for many years in the women’s category,” which is true. It slammed the IBA for what it considered inconsistent and arbitrary decisions to ban these two athletes, and said that the National Boxing Federations need to “reach a new consensus” over this issue before the 2028 Olympics in Los Angeles.