Tifanny Abreu was leading her team in a key volleyball match last month when the opposing coach called her a man.

Abreu is the first transgender volleyball player to compete on a professional women’s team in Brazil, and the comment was criticized widely in LGBTQ circles after it was aired on TV. But it also inspired critics of Abreu, including former volleyball star Ana Paula, to rush to the defense of coach Bernardo Rezende, who is better known as “Bernardinho,” or “little Bernard.”

“There’s a noisy minority that wants to force us to accept at all costs that feelings are more important than facts and biology,” Paula wrote on Twitter. “They are not.”

Bernardinho apologized, but his remark about the 34-year-old wing spiker rekindled a debate in Brazil about trans women and whether they should be allowed to compete professionally on women’s teams.

Scientists and international sports organizations have already weighed in on the matter. A 2015 study, for example, showed that trans women who underwent treatment to lower testosterone levels did not perform better in athletic competitions against other women than they did when they were in men’s sports competitions.

But the renewed focus on Abreu has fueled a debate in Brazil that experts say is unwarranted and based on fears and prejudice.

“It’s a misconception that her muscular strength or that of any other trans woman in the sport is different,” Alexandre Saadeh, the coordinator of São Paulo’s Transdisciplinary Gender Identity and Sexual Orientation Clinic, told HuffPost Brazil. “Biological and hormonal criticism is unfounded.”

The only thing that might distinguish Abreu from other women on the court, Saadeh said, is the distinct style of training she received in the men’s league before transitioning at the age of 29.

In his apology, Bernardinho said he was referring to Abreu’s technique when he called her a man.

“I apologize to everyone,” he said. “It was definitely not my intention to offend her. I was referring to the technical movement and physical control she has, which is common to male players.”

Abreu accepted the coach’s apology and, in an interview with Globo Sport, said she believed Bernardinho was referring to her technical movements, including a distinct approach to spiking more common among men’s teams.

“She started playing volleyball in the men’s league, so she has a cellular memory and a game perception from the time she had not made that transition yet,” Saadeh said. “But today, she has female hormonal patterns. This may have reduced her muscle base. She loses strength, but she is technical and tall. That doesn’t change.”

NELSON ALMEIDA via Getty Images Tifanny Abreu at a training in February 2018.

Abreu took a break from professional volleyball in Europe while she was transitioning and resumed playing at age 31, joining Italy’s second league. Back in Brazil and physically renewed, she was hired as a wing spiker by the Sesi-Bauru team in 2017.

She complies with the strict requirements enforced by the International Olympic Committee and the International Volleyball Federation.

The IOC allows trans men to participate in competitions without restrictions but requires trans women to meet certain criteria, including a testosterone level below 10 nanomoles per liter of blood. That’s the lower end of what’s considered normal in men. Players can be screened for testosterone levels in the 12 months prior to the first game and throughout the period of competition. Sex reassignment surgery, which was once required to compete, is no longer necessary.

The testosterone benchmark comes from an international standard that shows that women typically have 0.21 to 2.98 nanomoles of testosterone per liter of blood. In her blood tests, Abreu usually shows 0.2 nanomole per liter of testosterone, comfortably meeting the IOC requirements.

In the sexist and violent culture in which we live, if someone that was biologically born a man forsakes that masculine role in society by adopting a feminine role, this is viewed as frightening, incomprehensible. We still have a long way of acceptance to go. Natália Pereira Travasso, a psychoanalyst, author and advocate for LGBTQ rights

Abreu is considered a force on the courts. She holds the record for most points scored in a single match in Brazil and averaged the most points per game in the 2017 Superliga.

A recent survey by Brazilian website UOL Sports, however, pointed out that Abreu scores less and her performance fluctuates more than other players. In the game against Bernardinho’s team, for example, she was the top scorer with 27 points. But in the next match, she scored only eight. Her overall performance this season has declined from her peak in 2017 and 2018.

In an interview with UOL Sports last year, Abreu said she gets physically exhausted faster and has a more time-consuming recovery compared with other players.

“My hormone levels are so heavy that it ends up affecting my health,” she said. “Sometimes I think I would like to play for five or six more years, but I might not be able to do so.”

Experts note that the recent criticism directed at Abreu is not only scientifically unfounded, but it also reinforces prejudice and exclusion.

“This case reveals a lot about society’s conception of what women and men can and cannot do in sports, whether they are transgender or cisgender, and the very experience of transphobia,” said Jaqueline Gomes de Jesus, a Ph.D. in social psychology and a professor at the Federal Institute of Rio de Janeiro.

Natália Pereira Travassos, a psychoanalyst, author and advocate for LGBTQ rights, said Abreu’s critics were “reducing an individual to a biological issue,” which she said was a form of violence.

“In the sexist and violent culture in which we live, if someone that was biologically born a man forsakes that masculine role in society by adopting a feminine role, this is viewed as frightening, incomprehensible,” Travassos said. “We still have a long way of acceptance to go.”

Gomes de Jesus said the field of high-performance sports needs to address not only the rights of trans players to compete, but also their rights to dignity.

“When someone goes so far as to question an international rule, this only confirms the prejudice,” she said. “All criticism seems to be justified by the fact that [Abreu] is a trans woman. No one questions the performance of other players who have a similar muscle tone. This reinforces transphobia and exclusion.”