// If they aren't split in the academic side of mixed gender schools - where it's well known that girls can be ahead of boys by a significant amount and thus gain more prize//
You're conflating EQ development with IQ development

//If they aren't split in the academic side of mixed gender schools ......why should they be split on the sports fields? // non sequitur argument

Make a valid argument and drop the intellectual dishonesty before you insult me.

As for your question about Caster, it's simple, she competes with women, because she is a woman.