During childhood and young adulthood, the skeleton accrues virtually all the bone mineral it will ever have.¹ Since the aging process is associated with bone loss, the more bone mass one gains in the formative years, the less likely it is that increased bone resorption and decreased bone formation will result in osteoporosis. Hence, the failure to achieve optimal peak bone mass is a pathogenetic mechanism in osteoporosis. The sex steroids are critically important in helping to establish peak bone mass for both sexes. Girls with estrogen deficiency do not achieve optimal peak bone mass.²–⁴ Similarly, achievement of peak . . .