Using a candidate gene approach, men with osteoporosis and femoral neck bone mineral density of less than 2.0 SD below age-matched mean, are compared to a group of men with femoral neck bone mineral densitiy greater than 2.0 SD above the age-matched mean from the study entitled "Effects of Calcium Supplementation to 1500 mg/day in Elderly men on Parameters of Bone Formation". After obtaining consent, DNA is isolated from blood samples and purified. The purified DNA is then used with selected DNA primers for a selected gene by PCR analysis. The results of this analysis are then compared for the frequency of allelles in the two groups. This study is the first to look at the genetics of men with high bone mineral density.