I'd tell you teenagers driving is a LOT more dangerous in a much bigger way than throwing bb curve balls at 12. Given the level of STD's in teenagers I'd tell you sending them out on a date is a riskier proposition than early breaking pitches. You make your own call but it's as much an emotional decision as anything given our lack of risk averse behavior in other areas. I'm just telling you if you keep digging you will find no consensus. Many believe overuse based on the tendency to play bb and fp year round along with the tendency for bb pitchers to throw too little and pitch too much is the large factor. But I really don't mind if you are conservative with your kid. My concern ends with the notification that there are other opinions.