From infancy through young adulthood the activity of bone formation predominates, resulting in a steady accumulation of bone mass. As the rate of growth changes with age, so skeletal modeling progresses through phases of different intensity with time. This is paralleled by concomitant changes in bone and calcium metabolism. Bone modeling and skeletal consolidation probably result from a complex sequence of hormonal changes in interaction with nutritional factors. However, current knowledge of the role, sequence, and genetic regulation of hormonal events during puberty, and of the response of bone tissue in interaction with nutrition is limited. This interaction is now beginning to be elucidated. The importance of this interaction with regard to fracture epidemiology in children and peak bone mass acquisition has been discussed.