Despite years of intensive investigations, the etiology of benign prostatic hyperplasia (BPH) is still uncertain. To date, however, the powerful tools of molecular genetics have not been extensively used to investigate these mechanisms. In particular, genetic association is a powerful approach to identify genes and/or genetic loci that confer disease susceptibility. Family and twin studies by our group and others have provided strong evidence for genetics as an important factor in the development of BPH. These intriguing findings of a genetic susceptibility to BPH suggests that there are germline sequence variants in the genome predisposing to the disease. We feel that there is enough evidence for an important genetic component of BPH to justify a systematic search to identify BPH susceptibility alleles, and that progress in genome wide association technology makes such a search highly lil