JOHANNESBURG • "It's a ticking time bomb," Daniel Mothowagae says quietly in Johannesburg as he anticipates the furore that is likely to explode when Caster Semenya runs in the Olympic Games.

Apart from being described by many athletics specialists as an almost certain winner of the women's 800m in Rio, she will suffer again as she is made to personify the complex issues surrounding gender verification in sport.

Mothowagae, who works for The Sowetan newspaper and is friendly with Semenya, sounds innocent when saying: "Caster is just a tomboy."

His fellow sports writer, Wesley Botton, who has followed Semenya more closely than any reporter since her surprising emergence as a teenage world champion in 2009, laments the fact that "she has become the poster girl for hyperandrogenism".

Jean Verster, the athlete's coach, stresses that "Caster is a fantastic human being, a down-to-earth person and a great athlete who is like a mother to some of the girl athletes in our group".

Meanwhile, Ross Tucker, the eminent South African sports scientist, regrets the personalisation of hyperandrogenism, but he is "dreading the Olympics because Semenya will win and the fallout will be deeply unpleasant".

These contrasting South African voices are united by shared conviction. They all believe Semenya is about to unleash the full force of her supreme ability and smash a world record that has stood for 33 years.

But they also agree she will be confronted by an invasive scrutiny on her alone - even when there are "open secrets" that three of the Olympic 800m favourites might be inter-sex athletes.

Verster, South Africa's most accomplished running coach, concedes that "even now, I am trying to protect Caster".

The debate around hyperandrogenism is as poignant as it is thorny. In simplistic summary it asks us to decide whose rights need to be protected most.

Is it the small minority of women whose exceedingly high testosterone levels, which their bodies produce naturally, categorise them as inter-sex athletes?

Should their human rights be ring-fenced so that, as is the case now following an overturned legal ruling, they are free to compete as women without being forced to take medication that suppresses their testosterone?

Or should the overwhelming majority of female athletes be protected - so they are not disadvantaged unfairly against faster and stronger inter-sex competitors?

"We all differ in our opinions," Mothowagae says, "but for me it's a closed case. Caster is allowed to compete. CAS have made their ruling."

In July last year, CAS, the Swiss-based Court of Arbitration for Sport, overturned the 2011 IAAF (International Association of Athletics Federations) regulations that curbed testosterone levels in female athletes. They also suspended hyperandrogenism regulations for two years.

"Caster always tells me that as long as the rules say she can compete, she will run," Mothowagae says. "Rio will test how much officials have learnt from her ordeal at the 2009 World Championships.

"If Caster could survive it as an 18-year-old, she can face anything at 25. She is brave and she can look at the world.

"But the administrators don't seem to have any strategy even though we know Caster will be insulted again. She suffered psychological torture before but it's building to a new level. The bomb is ticking."

That ticking has been intensified by Semenya's blistering form.

After being in the doldrums for much of the period when she was compelled to take testosterone-suppressing medication, with other factors also bringing her down, she has produced some astonishing performances this year.

She won the 400m, 800m and 1,500m in imperious style one unforgettable afternoon at the South African championships in April and then, last month, ran 1min 55.33sec in Monaco. It was the fastest women's 800m time since 2008.

"She is proof of the benefit of testosterone to inter-sex athletes," Tucker argues. "Having had the restriction removed she is now about six seconds faster than she had been the last two years."

On July 27 last year, Semenya was liberated further when Dutee Chand won her landmark case at CAS.

The 19-year-old Indian sprinter was cleared to run competitively after her lawyers argued that her exclusion on the basis that sex-verification tests, relying primarily on levels of testosterone, were discriminatory.

All regulations around hyperandrogenism were suspended until July next year. Semenya was free to run naturally again - without testosterone-suppressing medication.

There is a chance that she could also run the 400m in Rio. Tucker has predicted the drama and vitriol that would erupt if she proceeds to beat the United States' most celebrated female runner, Allyson Felix, and wins the 400m before the 800m.

"I'm actually dreading the Olympics," says Tucker. "People only want to hear a good story, so when Semenya wins gold, the South African media will go crazy. If she breaks the world record, it'll be even crazier. (But) then we'll have terrible online abuse of Caster from the other side."

Verster is clear when asked if he agrees Semenya could obliterate Jarmila Kratochvilova's world record of 1:53:28 - set in July 1983.

"Yes I do. Of course I believe Caster can do it. But our main goal is to win gold and even though Caster ran the fastest time in eight years, in Monaco, on the all-time list it's not even in the top 20. We talk about taking baby steps."

Semenya's personal best is the 22nd fastest-ever women's 800m - but most of those quicker times were fuelled by doping.

The South African is running clean but, because of her natural testosterone levels, she is running towards trouble.

THE GUARDIAN