What is a gender test?and how does it determine if one is a man, woman or both?!?

I was filled with compassion for Caster Semanya, caught in the middle of this row. She's a mere child - only 18yrs for goodness sakes! How could they let this happen? Surely, any question about her gender should have been ironed out loooong before she arrived on the international scene? Good management and coaching would have seen to that, seeing that these allegations have followed her for quite some time. I'm all in support of her, but for those crying racism, forget it! She does look like a man, maybe more like a teenage boy. She appears to be completely flat chested, mascular torso and arms, deep voice, but without any bulge' y'now where'. No curve in sight. I came in the room while the heats were on and actually asked my son 'why is a man allowed to compete with women?' A few seconds later I realised she's supposed to be a girl. I wasn't too suprised that a gender issue came up. I must admit, that if I were a competitor, I'd want some answers too. It wouldn't be fair to expect females to race against a man. On the other hand, if a female simply has more male hormones and attributes, surely that cannot disqualify her? I mean, don't several athletes have genetic traits that give them athletic advantages over us mere mortals? Look at Usain Bolt for example. His performance in incredible, but one can see his height, build,strength, endurance and ability to move like lightning are a clear advantage. Besides, some female athletes look very masculine. Did they all get tested? This has raised some very interesting questions. I for one thought that to identify whether one is male or female, all one had to do was examine the plumbing. Apparently, it's not so simple, since sex and gender are completely different things. One's biological, the other is how one perceives and projects one's self. So we're still left with some rather confusing thoughts. XX,XY,XXYand variations...Lord have mercy! I sincerely hope, that the tests favour both sex and gender as female. After all, she was born and raised a girl. The fact that she's a natural head(yay!) , made no attempt at make-up or plucking her bushy eyebrows proves her innocence. We cannot pass judgement on this young woman. I hate to think if tests prove she's more male than female. God help us all. I will update when I know the conclusion to this drama.