...but the normal rough-and-tumble play of childhood shouldn't! If a child falls from atop a climbing structure and breaks a bone, then it may be a normal fracture of a normal bone. But if a child trips on a single step and breaks a bone, then the bone should be checked to be sure that it is healthy. Childhood is the time when the bones normally develop most of the bone density needed to last for a lifetime. Most of the calcium usually comes from dairy products. The August 2001 issue of Pediatric News warns that low-impact fractures can be a clue that a child's bones are weak. Too much soda, too little exercise, too much steroid medication, or too much thyroid hormone, for instance, can dangerously weaken the bones.