AMNA NAWAZ: The 2024 Olympic Games have garnered tens of millions of viewers with jaw-dropping performances and compelling storylines.

But in recent days, controversy surrounding the gender of one boxer has also consumed headlines.

William Brangham has that story.

WILLIAM BRANGHAM: Algerian boxer Imane Khelif was triumphant yesterday.

She defeated her opponent from Thailand and will now fight for gold on Friday night.

On the streets of Paris, Algerian fans rejoiced.

MAYA SILARBI, Algerian Supporter (through translator): It was an intense fight.

She gave everything.

Imane was able to represent her country.

She was able to show the world what strong Algerian women are.

She came out victorious and we are proud of that.

WILLIAM BRANGHAM: But Khelif's rise has also put her at the center of an international firestorm.

It began last week, when she defeated an Italian boxer here in blue who quit their match after just 46 seconds, saying she was in too much pain from Khelif's punches.

MAN: A man from beating a woman to death.

WILLIAM BRANGHAM: Immediately, social media and cable news was flooded with false accusations that Khelif was male or transgender.

Former President Donald Trump and Harry Potter author J.K. Rowling, both of whom have spoken out against transgender people, lashed out at Khelif's participation.

SEN. J.D.

VANCE (R-OH), Vice Presidential Candidate: The far left wants to allow biological males to beat the living crap out of women in boxing.

(BOOING) WILLIAM BRANGHAM: Khelif is not male or transgender, but these recent accusations stemmed in part from her disqualification at last year's world championships.

The International Boxing Association, or IBA, a governing body for the sport, barred Khelif and a Taiwanese boxer after the IBA claimed they failed unspecified gender eligibility tests.

The International Olympic Committee, which called the IBA's decision quote, arbitrary and banned the association over corruption concerns last year, decried the vitriol that's been aimed at Khelif.

MARK ADAMS, Spokesperson, International Olympic Committee: The Algerian boxer was born female, was registered female, lived her life as a female, boxed as a female, has a female passport.

This is not a transgender case.

WILLIAM BRANGHAM: Amid the attacks, Khelif's father came to his daughter's defense.

AMAR KHELIF, Father of Imane Khelif (through translator): This is our official family document, May 2, 1999, Imane Khelif, a female.

It is written here.

You can read it.

This document doesn't lie.

The people who are lying and leading a fierce campaign against her are the enemies of God.

The attacks against her are immoral, it is not fair.

Imane is a little girl that has loved sport since she was 6 years old.

WILLIAM BRANGHAM: Algerian fans have been solidly behind Khelif at the Games, and, this week, she spoke about the toll the criticism has taken.

IMANE KHELIF, Algerian Boxer (through translator): I send a message to all the people of the world to uphold the Olympic principles, to refrain from bullying all athletes, because this thing has effects, massive effects.

It can destroy people.

It can kill people's thoughts, spirit and mind.

WILLIAM BRANGHAM: So that was Imane Khelif a few days ago, describing what these accusations can do to people.

For a deeper look at what we do and do not know, and what this says more broadly about the future of women's sports, we are joined by Katie Barnes, who's been closely following this for ESPN.

Katie is also the author of "Fair Play: How Sports Shape the Gender Debates."

Katie Barnes, thank you so much for being here.

There are so many different threads in this story, who governs boxing, who gets to determine, who competes where, all these misconceptions about Imane Khelif herself.

But let's start with her to begin with.

She's born a female, she's lived her life as a female, she's competed as a female, and yet there's this international boxing association test that allegedly disqualifies her.

What do we know about that test and what it tells us?

KATIE BARNES, ESPN: The nature of the test itself is unclear.

The association has said that it was not a testosterone test.

In a press conference, they later clarified that it was a blood test.

But what they were testing for and exactly what eligibility standards Khelif did not meet, they have not been specific about.

And part of that is due to the fact that this information is private medical information, so they are limited in terms of what they can say publicly without the consent of the fighters.

WILLIAM BRANGHAM: So, at its core, it seems that there is this discrepancy between what the IBA and the Olympics say about whether or not someone has some unfair characteristics that allow them to compete or not, right?

Isn't that the core of this?

KATIE BARNES: Yes, there's the tension around the question of who it should be eligible to compete in the women's category in sports, in this case in boxing.

And there is a disagreement, it would seem, between the IBA and the IOC.

And, again, we don't know the specifics of the disagreement, but the IBA has vigorously defended its decision to disqualify Khelif and Lin Yu-ting.

And the IOC has vigorously defended its decision to include them both in women's boxing competition in Paris.

WILLIAM BRANGHAM: How often are these tests used?

Have they been used for a long time?

What can you tell us about the history of this kind of testing?

KATIE BARNES: I would say that sex verification testing in terms of determining whether or not an athlete who wants to participate in an elite women's category is eligible to do so,that has been around for a very long time, almost since women have been playing sports at the Olympic level, frankly.

And so those tests have taken different forms from visual inspections to cheek swabs that are looking for DNA tests or chromosomes to hormone tests over time.

And so they have taken different forms.

And in recent years, I would say it's been cyclical in terms of how these tests are performed and under what circumstances.

And so it's an ongoing discussion about how best to regulate the women's category.

And it is something that is unique to the women's category.

The men's category is not under the same type of scrutiny, largely because of the nature of how women began to get access to sports to begin with.

It's derived from this idea that this is a protected category.

And so, therefore, the boundary that is set must be policed from a regulation standpoint.

And so how that has happened has changed over time, but it's pretty much always been there.

WILLIAM BRANGHAM: So what do you make of the whole political firestorm that blew up over Imane's successes?

KATIE BARNES: I really think of it as a consequence of imprecise language.

When people use terms like "biological male -- quote, unquote -- and -- quote, unquote -- "man" to describe people who are competing in a women's sporting event, especially a combat sports event like boxing, that tends to bring out a lot of emotion from folks.

And that is also happening in the wake of just a tremendous amount of emotional and legislative energy being put toward addressing some of these issues in the United States in terms of legislation passing around transgender athletes.

And so I really think that bred a lot of confusion and brought out a lot of emotions.

And sometimes that was used inadvertently and correctly.

And sometimes folks, I think, weaponized that in this particular case.

WILLIAM BRANGHAM: I mean, apart from these larger debates over these -- who governs these rules and who sets these standards, as we heard from Imane Khelif herself, the vitriol that was directed at her about -- towards an individual has got to be so dispiriting when you're trying to compete at this level.

KATIE BARNES: Yes, I can't speak for her, of course, but judging by what she has said publicly, and also, what -- how she just released so much emotion after winning her quarterfinal bout, you know, it's very clear that this has weighed heavily on her.

And other athletes who have been through similar difficulties when they run-up against policy that disqualifies them and that becomes public, I think it's important to acknowledge as members of the public that these are real people who are wrestling with these things and perhaps are learning new information about themselves.

And now that's being parsed publicly and in highly emotional and charged ways.

And athletes are human too.

And I think we would be -- we would do well to remember that.

WILLIAM BRANGHAM: All right, Katie Barnes of ESPN, thank you so much for helping us wade through all of this.

KATIE BARNES: Thank you for having me.