Side-arm

Question
My son is 13yrs.old and plays in a league. He is a 1B, 2B, 3B. He is a natural side-armer,he has never been an overhead thrower. I hear so many pros and cons about side-arm throwing-I've even had coaches wanting to change him to overhand to throw with more speed.His aim is pretty much dead on playing the field but I don't want him to ruin his arm because of stupidity.Natural side-armers are rare and it seems proper teaching techniques are even rarer....Please,any help would be appreciated.
                                   Jose  

Answer
Alot of infielders throw side arm.I think a player needs to learn how to do both.It may also limit were he will play on the field.He may be a second baseman because of his lack of arm strength.Bad throwing mechanics can't be easily fixed.Throwing side arm could lead to series arm problems.