No rule on curve balls. My son throws an effective one that is at times nasty. I can't take credit for it as I couldn't get my curve ever to break sharply. He's still working on command of it though and he's getting better. If he throws 90 pitches in an outing, he might throw the curve 15-20 times.

My older son, whose season was affected this year by illness, doesn't throw the curve as often. He throws a hard cutter though and is very successful when he's keeping it down in the zone.

While there is no ban of curve balls, I was at a teener game last year when the umpire told the manager and 13 year old pitcher that too many curves were being thrown and if the kid threw another one, he would eject him and the manager.

I know of one boy about 7 years ago in our area who threw a lot of curves when he was 12 or 11. He's had two surgeries on his elbow. There is some thought the curves contributed to it as well as the fact that he was overused on multiple teams by his dad.