That doesn't mean your kids aren't getting enough of the mineral, though. Many foods and drinks today are made with water that contains fluoride, so your children may be consuming enough of it to compensate. There's fluoride in their toothpaste, and fluoride treatments are part of a routine dentist's visit. In fact, getting too much fluoride can damage and discolor the enamel on unerupted teeth.

To be sure, have your water tested by an expert to see how much fluoride is in it  -- check with your local water department or department of public health for details  -- and then talk to your doctor. He'll help you decide whether his prescribing a supplement makes sense.