“we have to keep things fair” ← → “we can’t really keep things fair”
It’s a paradox.
Take a close look at Michael Phelps. His body proportions are very unusual — -and freakishly good for swimming fast. But NO ONE would say “his body gives him an unfair advantage: keep him out!”. No, for some reason it’s ONLY chromosomes (and the hormone levels they indicate or imply) which are tested for.
I understand, in the age of steroids, why an “unusual” hormone level prompts a closer look. But at the highest level of athletics — -indeed, the highest level of ANYTHING — -there is a basic unfairness. Some people are unfairly gifted: was it ever thus.