Males vs Females in Competition

[Jester]

And in those, no, there should be no difference from just gender, of the horse or rider.

[DesignFox]

I'm in a sport where males and females can compete on a level playing field. Both in the saddle and under it

hahaha good point!

[AFPheonix]

Although back to racing, fillies can indeed run with the big boys. Just look at Ruffian.
Unfortunately, Thoroughbred breeders anymore breed for horses that are flashes in the pan and break down very quickly. They're breeding stamina and good legs and feet right out of the breed. Barbaro, Eight Belles, and Big Brown are all victims of this short-sightedness, as are countless more animals that don't have big names behind them. It's an epidemic in a lot of specialized breeding these days, but race horses are some of the most visible of their species to non-horse people, and therefore will catch the most attention.