Semenya, 25, has testosterone levels three times the normal level found in women and approaching those of a man. Furthermore, she has no womb or ovaries, and instead, owing to a chromosomal abnormality, internal testes.
As a result, her appearance is startlingly masculine: her face and physique bring to mind the likes of those East German female hammer throwers of the Sixties and Seventies, whose young bodies were irredeemably masculated by cruel state-sponsored doping programmes.
There are those who say she should not be allowed to compete in the Olympics women’s 800m, which she is almost certain to win. No doubt they would also like to see her stripped of her former victories, gold and silver at the 2009 and 2011 World Championships and silver at the London 2012 Olympics.
It is not accusations of doping that haunts the South African, though it does come down to chemistry. The question is whether she is, in fact, a biological woman.
Though Semenya, as is her right, identifies herself in societal terms as a woman, many in the world of medicine would describe her as intersex or a hermaphrodite.