Will my kid become aggressive?

Will my kid become aggressive?
So, will martial arts training make your kid aggressive, seek out fights, and will it be safe?
This is a really common and frankly a reasonable and smart question. You go to a martial arts school, you're introducing other people to your child that are going to be mentors in some way. A lot of how that school is going to help them is going to have to do with what kind of mentors you're picking.
You have to think of the martial arts school as being part of your team as a parent. That's a big deal. Just like if I were going to, for my son, hire somebody to teach him how to paint. I do not draw well. If I was going to get him a teacher for painting, I would sit down and speak to the teacher. Can I hold a conversation with this person? My son's going to absorb some of their mannerisms. Am I comfortable with that? Am I okay with that?
If you really want to find out, I would take classes with that painting instructor myself so I can really get a vibe on what kind of person they are and see how they work. Then when my son is having something that he's studying or having problems or challenges, I can really understand what he's doing and go into it with him. I'm still able to be a parent, but I also look at him as just another person. He can look at me as another human being who is learning something. While they're learning how to paint, I would also be teaching my son how to learn, how to be a good student.
From there, look at the way they train. If you're not going to take class with them, because not everybody can, watch the way they train. You don't have to sit for every class, but sit regularly. I'd say at minimum one to two a month and just watch. See how they train. Do you see things that are questionable? Are they always wearing mouthguards? In the case of jiu-jitsu or taekwondo, the things we teach here, the moment that they're sparring each other, mouthguards, in the case of taekwondo, full pads, cups for the boys, everything. Or is there a lot of striking that's happening that's, well, you have to toughen up. You have to be careful.
I know in some Japanese martial arts they'll be punching a makiwara board, which is a thing that conditions the knuckles, and then they also break pine boards. Those things, just making sure that that's done reasonably. In general, watch for that.
