Changes in bone mineral mass by DXA at the time of puberty and its accompanying growth spurt have been reported in both males and females (Glastre 1990, Gilsanz 1991, Rico 1993, Mora 1999). However, the reference standards generated by DXA manufacturers and recent longitudinal studies are age- and sex-specific only (Bachrach 1999). Reference standards based on age or puberty only are not helpful in evaluating patients with disorders, such as HIV infection, which affect growth, timing of puberty, and may independently affect bone mineral acquisition (Leonard 1999, Thearle 2000, Arpadi 2002).