Taiwanese boxer Lin Yu-ting became the second boxer at the centre of a gender eligibility row to secure a medal at the Paris Olympics as she reached the semi-finals of the women’s featherweight division.

The 28-year-old beat Svetlana Staneva, 34, by unanimous decision – but after the bout the Bulgarian’s coach suggested Lin should not have been allowed to compete.

A visibly frustrated Staneva, 34, left the arena making a cross with her fingers, shouting “no, no”.

Like Algerian welterweight Imane Khelif who progressed on Saturday, Lin is competing in Paris despite being banned from last year’s World Championships by the International Boxing Association (IBA).

The fighters were reported to have failed gender eligibility tests at the Worlds, a situation which has sparked huge controversy.

In an interview with BBC sports editor Dan Roan on Thursday, IBA chief executive Chris Roberts said XY male chromosomes were found in “both cases”.

The International Olympic Committee (IOC), which is running the boxing at the Olympics, has raised doubts about the accuracy of the tests.

The BBC has not seen the results and, as yet, has not been able to determine what the eligibility tests consisted of.

“I’m not a medical person who should say if Lin could compete or not here, but when the test shows that he or she has the Y chromosome she should not be here,” Staneva’s coach Borislav Georgiev told BBC Sport.

Lin will face Turkey’s Esra Yildiz Kahraman in Wednesday’s semi-finals. Even if she loses she will take home a bronze medal.

Lin and Staneva met in the quarter-finals of last year’s World Championships with Lin winning before she was disqualified. As a result, Staneva was promoted to bronze medallist.

The IBA said Lin had “failed to meet the eligibility criteria for participating in the women’s competition, as set and laid out” in its regulations.

But the IOC has strongly defended both Lin and Khelif. President Thomas Bach said on Saturday there was “never any doubt” the pair are women.

The Russia-led IBA has also been suspended by the IOC since 2019 because of concerns over its finances, governance, ethics, refereeing and judging.

In the ring, a scrappy fight threatened to boil over at times with Staneva regularly complaining about Lin’s use of elbows.

She came out swinging in the final round in an attempt to overturn a deficit but was caught by Lin’s blows.

“Svetlana is a professional boxer,” her coach said. “She’s not interested in who is going in the ring against. She wants to fight.”

“In last year’s championship Lin had an advantage by the referee against Svetlana and here she has the advantage [over use of elbows] again.”

The situation, which has sparked wide debate online, could take another turn on Monday after the IBA said it would hold a news conference “dedicated to the detailed explanation of the reasons for the disqualification” of Khelif and Lin at the 2023 World Championships.

Khelif fights in her semi-final a day later.