My boys do judo, karate and football, typically thought of as boy sports (I've actually heard a Mum tell her daughter than no she couldn't do karate, they would find her a girls sport, like dancing)They actually have the same 2 instructors for judo and karate, one man and one woman. And there are a couple of girls at judo and were 2 girls in ds1s first football team. And let me tell you, at competitions, the girls have so much more 'fight' than the boys at judo!
I am so overly paranoid though, ds3 enjoys dancing and I'd love to take him to a dance class. I used to dance and we had 2 boys in our dance class. But I always feel people will be like "she made that one do dancing because she didn't have a girl to take". I'm the same with DS2s hair. He like to have it on the longer side for a boy. But I worry that if it gets 'too long' people will think I've let it be like that just so I have some hair to brush.