You're listening to the inquiry on the BBC World Service with me Helen and Merriman.

Each week, one question, four expert witnesses and an answer.

Rio 2016, eight women are lined up on a track, years of training behind them, the hopes of a gold medal in front of them.

They tear along the track, soon coming into line,

and then it happens.

One breaks out, each stride taking her further and further ahead,

until no one can catch up. 800 meters from the start line, she's done it.

Kasta Semenya has won Olympic gold.

As she celebrates her win,

Lindsay Sharp, a competitor, stands to the side in tears.

Not because she's been beaten, but as she makes clear later, because she feels she's been

beaten unfairly.

She was entering a toxic debate.

What to do about female athletes like Kasteosomenia, whose natural levels of testosterone

are usually found only in men.

The I-A-F, athletics governing body, thinks it has an answer.

In less than two months, they'll introduce new rules to target these athletes, but these rules have proved

highly controversial. An open letter signed by 60 female athletes says they undermine the

spirit of sport.

Kasta Semenya is taking legal action against them,

and Human Rights Watchers even weighed in,

describing them as a violation against women.

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