The strengths of our study include the following: (1) novelty, as this is the first study to implicate the role of PRDM16 in the molecular mechanism behind the positive effects of T therapy in vivo on bone in hypogonadal men; and (2) our study is the first to explore gene and protein machinery involved in the enhanced osteoblastogenesis in men with hypogonadism given T therapy. The gene discussed is PRDM16; the disease is hypogonadism.