A lot good points being made, some went in a different direction. All of us can agree that a young kid can get many skills sets and learn by playing different sports. I would argue that basketball and soccer have more in common then you think. 1. decision making, or speed of play. both very important. 2. zone and man defense. 3. moving with out the ball. 4. reading the game. 5. transition or counter attacking. 6. momentum change/swing. 7. How to protect a lead/come back for a win. 8 etc.

Now if you think playing QB or OL is easy , think again. How many of you , that played, can tell the difference b/w cover 1, 2, 3,4, 2 man, man free, man under, and then be able to read the blitz package, and coverage change when a blitz is coming. Now you only get 25 sec to call play get to line and look at defense and figure all that out. sounds easy right? Now the OL guy has so much more to do, odd front, even front, LB coming, is he in a 1, 2, 2I,3,4,4I,5, 6, 9 tech? Confused yet? Now if the DL shifts or stunts on the snap, wow now what do you do?
I will stop here, I have had enough fun. But if a 12 year old wants to try another sport, I believe he should be allowed to do that. I also believe that the other coaches should work with that child. When the get older if they want to focus on only one sport then so be it. But how many of you can play other sports well? I can tell you that a lot of soccer kids can not judge a ball in the air. Why is that?