I read the story then found a picture of the runner in question. I can see why people are questioning her gender because the picture I saw looked like a man. Granted I have known women who looked more like men than women. So who knows. If she is just a masculine looking woman, I hope she is ex-honorated and it puts an end to the questions about her gender, however if she is proved to be a man, then I foresee a whole new can of worms opening up. In a world with sexual reassignment surgery, would disqualifying a person from a sport based basic gender testing as mentioned in the article qualify as discrimination? I don't know how a court would rule on this if challenged.
It's already happened in the past. Ewa Kłobukowska was banned from competing eventually.
In any case, it doesn't matter how they do this, either, since the Olympics are essentially private events. It'd be like if a woman who tried to join a male pro baseball team sued. Doesn't work.