I was wondering what the general Jewish outlook was on teaching kids martial arts (kung fu or similar) for self defense from a young age. My son isn’t the type who is aggresive and I am wondering if it would be good to get him to learn how to fight. Or would this possibly encourage him to go on the offensive where he shouldn’t due to feeling bore courageous?

In my opinion it is a very good thing to teach your son self defense. It will not make him overly aggressive or violent. In most cases it will do the opposite, for it will give him a safe place to take out his aggressions. He will save his fighting for his training on the mat or the ring instead of the street or the school yard. It will teach him self control and mutual respect of his opponent. It may also come in handy one day. In all self defense classes they teach the students to avoid fighting and use the fist only as a last resort. It will give him self confidence and a feeling of self development. There may be a halachick question with sports like boxing and kick boxing as apposed to wrestling and judo, for you are not allowed to hit your friend even if he allows you to hit him, so the training could have this halachik problem. (see Shulachan Aruch Harav hilchot Nizkai Haguf # 4. p 885) But I think that since they have boxing gloves and helmets and there is mutual benefit in the athletes sparing since it is the only way they learn how to fight it could be considered self damage for benefit which is permissible. (see Igrot Moshe Choshen Mishpat vol 1:103 and vol 2 :66)