I agree, I believe in this day and age it is nearly impossible to discuss any possible correlation between any sort of innate/genetic differences (and often even early-learned cultural differences) and mental ability without being branded a sexist/racist etc. No matter how many caveats one offers, no matter how strongly one emphasizes that it could be one, even a tiny one, of a number of factors that account for differences in achievement, it is basically not discussable without grave risk to one's profession and reputation. I find this particularly surprising because physical performance obviously has such an enormous genetic component.
Maybe one day an intelligent AI can tell us how our bodys work so we can stop the guessing game.