In private life it might not matter whether Caster Semenya is male or female, but it matters in international sport.
When is a girl not a girl?
The controversy surrounding Caster Semenya reached a crescendo this week when she won a race by such a huge margin that suspicions could no longer be contained.
There are many in the athletics community who feel that Semenya may be transgender. I don't think there's any suggestion that she is deliberately cheating, but perhaps that certain female hormones and characteristics may be lacking. She has a muscular build, a deep voice and has never developed breasts.
The tests she must now undergo are not in order to see if she's a man, but whether she 'qualifies' as a woman. If she cannot test positive, she can longer compete in women's athletics, as this would put her at too great an advantage - men develop more muscle than women and have a greater oxygen conversion which enables them to run faster.
Gender is such an integral part of who we are that many of us don't stop to think about it - we are simply male or female and that's that. But life is more troublesome for people who stand on the cusp.
Because, scientifically speaking, gender is not a cut-and-dried affair. In the womb we all start out female and masculine characteristics only develop later. We have varying amounts of sex hormones. Women need testosterone. Men need oestrogen. At puberty, some people's hormones fail to kick in and can leave them in no-man's-land. One friend of mine, at 17, turned out not to have a vagina, uterus or ovaries - did this make her not-female?
Just as most of us knew someone at school who was obviously gay, even at a very young age, I wonder if most of us have also encountered someone who is fixedly transgender.
I went to school with one such person. At birth, his sex couldn't be determined, so he was raised as a boy. However, he failed to develop sexual parts, and the other boys, at around the critical age of 11 or so, began to make his life a misery. It was far too late to 'change' him to being a girl, and as a hermaphrodite he endured years of bullying and insults.
Pretty much the same sort of thing seems to have happened to Semenya. Her interests have always been 'boyish', and she has spent her life being teased and humiliated for her masculine looks, with other competitors even refusing to share the toilets with her.
I can't imagine that this story will end happily if it found that Semenya is not entirely female according to the distinctions required by world athletics. Not only would she be banned from competing in women's races, her position back in South Africa might be untenable in a culture where there is already terrible prejudice against women who don't follow a traditionally submissive feminine route.
One can only hope, for her sake, that she passes the tests and turns out to be simply a new physical type (much as the muscular appearance of Navratilova startled women's tennis when she first appeared). Because, if not, I don't see how there is a place for her outside of the West, where some of us, at least, are more tolerant of difference.