Sad. Utterly sad. Most kids are still growing in their late teens, and is it not true that during your 20s, your bones are still strengthening? Why in the world are they disfiguring these kids digestive tracts, impairing nutrient absorption, before they've even stopped growing and laying down bone? Why not wait until they're older? Heck, most doctors won't even perform a vasectomy or tubal ligation until you're 30.