I agree with the previous comment in regard to "why risk it". But I will add that the curveball is thrown in a differant manner than when I grew up. When I grew up we were "taught to snap our fingers" to get a good break. This is also the form that causes Tommy John surgery. I do know from my talks with pitching coaches that there is a differant form that pitchers are taught to throw curveballs, and it is safe on the arm. Even after a couple of sessions with a cetain pitching coach, I still don't teach curveballs. In addition, if I see one of my players trying to throw one, I won't pitch him. At 12 and under, I don't see any reason to throw curveballs, so I am not going to take the risk. I will let the high scholl coaches teach the proper form for throwing a curveball, I'll take care of throwing mechanics at this level.
This seems like an older post, but I want to add my opinion. First off, I have coached a team for 6 years, and I have tried to give equal playing time to each child. This has been a recreational team that I have coached, so I felt that it warranted equal playing time. As my son has gotten a little older, I am consiering a move up to a more competitive league, and play in some tournaments. I believe that I would have to modifying my practice of equal playing time. I am also going to try to consider the long term consequences of not playing certain players. If I don't give a player enough playing time, I don't think that they will be willing to come back to my team the next year. This would mean that I would not be able to develop young talent. This will also hamper the ability of the team to get better on a season by season basis. I would be constantly trying to recruit new players to replace players who left to find a team that would provide more playing time. In watching other competitive/traveling teams, I have noticed that the better teams work each player into meaningful playing time so that each player feels they are a part of the team. This seems to be a tricky part of competitive baseball, if you don't give playing time, you will constantly be looking for new players. I can provide an example of the team that my son played for this year. He tried out for and made a competitive team in addition to the recreation team that I coach. The team was trying to replace 7 players from the previous season because those players did not feel they were part of the team, so they left. There are 3 coaches as well as 2 "friends" of the team, and that pretty much makes up the infield. The coaches rotate the catcher and the outfield, while the coaches kids and friends never play outfield or sit on the bench. While this is a pretty good team, I have heard the coaches asking what they have to do to keep the kids happy and keep them on the team for the next season. If they can't see what they are doing wrong, I don't want to get in an argument, so I am just going to have my son finish the season and see if he wants to return next season. I already know he does not. But this is a good team that get's worse each season because they don't develop talent, and many of the players feel like outsiders. It is also interesting that I have heard the coaches comment that they are getting beat by teams that they used to beat in the past. In addition, I see that as the season goes on, they are getting beat by teams they beat earlier in the year. Just my $0.00