On Saturday night, Caster Semenya won the 800m in 1min 55.28sec. It was a personal best, a new South African national record, and the fifth-fastest time in Olympic history. And it just may be that she never gets to run so fast again. Semenya, 25, is hyperandrogenic and the IAAF believe that she, and all other hyperandrogenic athletes, should not be allowed to compete unless they take action to suppress their naturally high testosterone levels.

The court of arbitration for sport disagrees, and in July last year it gave the International Association of Athletics Federations two years to produce evidence proving exactly how much of an advantage hyperandrogenic runners had over everyone else. Just two hours before her race, the IAAF’s president, Sebastian Coe, said again that the governing body will soon go back to Cas to try to overturn that decision. Officials are confident that the move will succeed.

Unlike Coe, Semenya had refused to speak all week. She has grown sick of the scrutiny. But winners are obliged to give press conferences, so on Saturday night she had no choice. She was so eloquent those listening could be forgiven for wondering why she hadn’t done it more before, until they remembered Semenya never asked to be put in this position, and that her body is no one’s business but her own.

Semenya explained that Nelson Mandela had once told her “sport is meant to make people feel united” and that’s what she is trying to do. “I think I have made a difference,” she said. “I have meant a lot to my people. I have done well. They are proud of me. And that was the main focus. I was doing it for my people, the people who support me.”

Semenya is not the only hyperandrogenic woman competing in these Olympics, just the most successful. It was the Indian sprinter Duttee Chand who took her case to Cas, where she accused the IAAF of discriminating against her by setting an upper limit for the testosterone levels of female competitors. But Chand didn’t make it through the 100m heats, and the IAAF is most concerned about the impact of hyperandrogeny in the middle and long distance events. The unpalatable but unavoidable fact is that while neither of the other two medallists, Burundi’s Francine Niyonsaba and Kenya’s Margaret Wambui, have identified as hyperandrogenic, both been subjected to the kinds of innuendo that Semenya herself experienced in 2009.

All three were asked to comment on whether the IAAF had made them take hormone treatments to suppress their testosterone levels and, if so, what effects those treatments had. Semenya’s times worsened considerably when she was taking the medication.

After a brief consultation with each other, all three refused to answer. “Let’s focus first of all on the performance today, let’s not focus on any medication,” said Wambui. At first Semenya’s reply sounded similar. “Excuse me my friend,” she said, “tonight is all about performance. We’re not here to talk about the IAAF, we’re not here to talk about speculation, tonight is all about performance. This press conference is all about the 800m that we ran today.”

Indignation was swelling in Semenya’s breast. And when she let it rise, what poured forth was more than extraordinary. Asked how, exactly, she felt she had made a difference to her sport she replied: “I think it is all about loving one another. It’s not about discriminating against people. It is not about looking at how people look, how they speak, how they run, it is not about being muscular. It is all about sport. When you walk out of your apartment you think about performing, you do not think about how your opponent looks. So I think the advice from me to everybody is just to go out there and have fun.”

So many South Africans have united behind Semenya, using the twitter hashtag #handsoffcaster. Listening to her talk it was clear they are motivated by much more than chauvinism.

Inspiring as Semenya’s words were, the truth is that her competitors don’t all think like she does. Britain’s Lynsey Sharp, who finished sixth, was congratulated on Twitter by her team-mate, Nigel Levine, who wrote “Happy for Lynsey Sharp for coming 3rd in women 800m”.

Sharp, who wrote a paper on Semenya while she was studying at law school, has seemed to struggle to contain her emotions this week. On the BBC, Paula Radcliffe explained why she felt Sharp was so upset. “However hard she goes away and trains, however hard Jenny Meadows goes and trains, they are never going to be able to compete with that level of strength and recovery that those levels of elevated testosterone brings.”

Radcliffe said that Semenya and the other hyperandrogenic women should either “take the medication to suppress the levels, or they choose to have an operation or they choose not to compete”. Incredible as this sounds, Radcliffe is right that several hyperandrogenic athletes have undergone major surgery at the behest of athletics officials.

In 2013 it was revealed that four young female athletes from developing countries, all with atypically high but entirely natural levels of testosterone, were sent to a clinic in France where doctors proposed removing their gonads and partially removing their clitorises. All four agreed, and a year later they returned to competition.

Hyperandrogenic athletes need protection. So do the runners such as Sharp, who feel, with good reason, that they are competing at an unfair disadvantage. There are no easy answers, and precious little agreement. As for Semenya, she is stuck in the middle, a human rights pioneer to some, something near a pariah to others. She said that her coaches had told her to try and forget about everything but her running. “I know what I can do,” she said, “I just want to be a better athlete.”

And on Saturday night, as she crossed the finish line and celebrated her win by flexing her biceps and brushing imaginary dust from her shoulders, she looked like nothing other than what she is. A happy, proud, and brilliantly talented woman.