Is it safe to let 12 year old throw curves?

I've been throwing curves since elementary school(they developed and got better later obviously) and havent ever had any arm problems. It's not the fact that curves are dangerous it's how they throw them teach your kid the correct form now so he can be really nasty in a couple of years. Also teach changeups I started throwing them last year and if u know where to put them they are just as nasty. Finally have your kid do long toss make his arm stronger and more durable that will prevent arm injuries