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Caster Semenya is one of the best 800m runners in the world - but her career has been dogged by controversy. She has had to undergo tests to allow her to compete in women's athletics - and was diagnosed with hyperandrogenism, her testosterone levels far in excess of the vast majority of women.

At one point she was told she had to take medication to reduce her testosterone level.

That rule has now been scrapped - but her appearance at the Rio Olympics has re-ignited the debate amongst some commentators.

Tabiso Tema, is a presenter on the Super Sport TV channel in South Africa and says it's not fair on Caster.

(Picture - Caster Semenya of South Africa at the 2012 Games in London. Credit: Clive Brunskill/Getty Images)