Diagnosing if your son has ADHD

Does my son have attention deficit disorder? I know it is a legitimate and existent and documented condition, but really, he is seven. Are not all seven year olds hyper and unable to stay focused on something for more than a few minutes? His teacher is worried, but I talked to some of the other parents, and apparently the teacher has thought over half her students has ADD. I have tried familiarizing myself with it online. There is a wealth of knowledge about it but there is nothing that I feel like I can use to determine absolutely whether or not my son has it. It sounds like my teacher is paranoid, but what if there is something local in the community or environment that is actually giving all of these kids ADD? I hate not knowing, it drives me crazy. It is almost giving me ADD just thinking about it.

Jim Walters