Seagull58
In the Algarve
The vast majority of elite showjumping, eventing and dressage horses are male (or neutered males). It's the horse that does the physical work, not the riderHappy to engage on that wider discussion. It seems to me accepted that sex is objective while gender is subjective and the question is how you order society on something subjective. Ideally you would not want society ordered: there should be no need for separate best actor/actress categories if there were even representation. But were there is a need then you require objectivity, sport being an obvious example. Even then it's clear that there might be some sports where sex is not a defining measure of success (equestrianism being a commonly quoted example) and then you don't divide.
The wider question is do you need to define gender if it doesn't determine a different outcome? If sex is actually significant in a given situation, should gender override that?