Sean B. wrote:
Sorry, maybe I wasn't clear with what I was trying to say.
I wasn't saying the rules were based on chromosomes. I was saying that the rules were made only for certain DSD conditions. My understanding is that these particular DSD conditions that the rules apply to, do not occur in people that are XX. Therefore any of the DSD athletes that are not allowed to compete in the mid distances cannot be XX.
It is also my understanding that a natural XX women would not be subject to the rules that would prevent them from running 400-mile, even if their testosterone is naturally high. Though I don't know if natural XX women can even have testosterone levels that reach the levels for the DSD rules to apply.
Actually there are XX women who can reach the testosterone levels of men.
There are also XY men who can have the low testosterone levels of women.