Will learning to fight make my kid more aggressive?

Nearly always the opposite, and every decent parent asks me this.

The loud kid who talks about fighting is usually the kid who has never done any. He does not know what he can do, so he keeps testing it on other people. Put him on his back a few times by a grown man who was not trying hard, and that urge goes quiet. I do not have to lecture anyone about humility. The mat does it for me.

The rules come before the skills, not after. You never start it. You never use it on someone smaller or someone who is not fighting back. You get an adult, you walk away, you tell somebody. What you are learning is for the day walking away is not on offer. I say that in the first session and I keep saying it.

There is one piece of grappling that teaches it better than any talk, and that is tapping. Your kid learns that losing is a thing you say out loud, straight away, without drama, and then you reset and go again. A child who taps fifty times in an hour has practised admitting they were beaten fifty times in an hour. That does not build a bully. See what tapping means.

The other thing it gives them is somewhere for the energy to go. A kid who has emptied the tank is not the kid looking for trouble at the bus stop.

Quiet kids get the same benefit from the other end. What they gain is the ability to hold their ground. See training a shy kid. If listening is the real worry rather than aggression, whether your kid will listen to a coach is the honest answer to that one, and if something is going on at school, tell me rather than let me find out later. See a teen who is getting bullied.