When my son did martial arts they segregated as a rule for sparring
All things considered few women match real men physically....karate or not
Maybe a woman at super top form or these boxer gals or the aforementioned giant 300 pound black behemoths
Its just how its always been....
Contemporary illusions brought on by washing machines and other comforts notwithstanding
Class size is too small for male/female split. And sparring isn't really a big part of it.
http://www.kickstartkids.org/about-ksk/
I don't mean to suggest there are not significant differences. And I believe in Chivalrous behavior is good for our society and individuals.
That said, I only have girls. I don't teach them to depend on the good behavior of others. Expect it, demand it of themselves and those the associate with, but don't depend on everyone exhibiting it.
My only point, today's world is not a clearly defined as it was many decades ago. Children need to be taught judgement, not just Black/White rules.