As I understand, CS has XY chromosones. I believe she has a condition (PAIS?) which makes her cells only partially respond to the androgens she produces, so that she has developed a body with female external genitalia rather than male ones. However, she has internal testes and no womb or ovaries.
It's a minefield.
Perhaps a good initial starting point is to return to first principles: i.e, "Why do we have a separate women's category in the first place?"
The only real reason we do it is because otherwise, top-level athletics would basically become "this thing that blokes do," there wouldn't be any female athletes in the media etc.
So women would feel like "top level athletics is not really anything to do with me." Perhaps this would result in less female interest in sports in general and so on. The parents of little Jimmy and Jessica (who both show tremendous talent at running) might consider getting little Jimmy into some really serious traininghe could become an Olympian!but of course they wouldn't do that to the same extent in the case of young Jess. Why bother? She won't win athletics medals. Girls don't do that. Perhaps this would gradually have a chilling effect on women's and girls' athletics in general, in the long run.
Sooooo..... let's say that 20 years from now, most medals in a lot of athletics are basically going to intersex women and transwomen. Would that feel like... kind of the same thing? Would women experience a sense of loss--a sense of "People who look and feel like us and represent us are not at the Olympics?"
I don't have any clear answer to that question. I wouldn't rule it out, though. Looking at some of the responses, here it's clear that to many people there was something a little jarring, at the gut level, about the sight of this race being won, across the board, by women who, let's be honest, did present a very masculine profile.
Of course, one might say "That is a silly reaction and women should not feel that way." But if women do feel that way... you can't just tell them to stop feeling that way. And if, in the future, the women's category in many sports starts slowing ceasing to fulfill its function of making women as a whole feel "represented" by the Olympics, well, what is the point of having it? Because the women's category does not really have any other function, does it?
I do know that right now, as of 2016, if I had a daughter who showed serious promise at running, I would be a lot less likely to think about "My God, could this child possibly be a future Olympian? Should I talk about getting them into some serious training??" than in the case of a boy, because I feel like we are seeing the writing on the wall right now.
As it happens, I don't give a shit about sport and think it's mostly a waste of time anyway, so from a selfish point of view I don't actually care that much. But if we do start to see some of these awkward tradeoffs between women's sport vs being inclusive towards trans and intersex athletes, well, I can see how it would potentially suck for people who really are interested in women's sport.