Genes play an important role in the development of osteoporosis. Twin and family studies have consistently shown that peak bone mass, ultrasound properties of bone, skeletal geometry, bone turnover, and fracture are heritable. Yet, as we report in this paper, few candidate genes have been implicated without ambiguity. Osteoporosis is thought to be a polygenic disorder, determined by multiple genes and environmental risk factors, each with small to modest effect on bone mass and fracture. Here we argue that future success in finding genes is only possible with improved study design and the use of more rigorous analytic approaches that are now becoming available.