If you think your kids need milk to grow strong bones, it's time for a second opinion. A comprehensive review article published in Pediatrics in 2005 showed that getting extra calcium—from milk or anything else—makes no difference in bone density in children or young adults. And evidence shows that dairy product consumption contributes to obesity, ear infections, constipation, respiratory problems, heart disease, and some cancers.

A major study shows that the amount of calcium girls consumed during the teen years had no impact on bone strength. Exercise, however, had a huge positive effect. For strong bones, kids need weight-bearing activity, sunlight, and a diet rich in fruits and vegetables. And there's healthy calcium in fortified juices, soymilk, greens, beans, and many other foods that avoid milk's problems.