Azoospermia due to low sperm production (non-obstructive azoospermia) affects approximately 1% of the male population and 10% of men who seek fertility evaluation. Testis biopsy reveals that these men have Sertoli cell-only pattern, maturation arrest, or hypospermatogenesis. Until recently, it was assumed that men with non-obstructive azoospermia were untreatable. Indeed, these patients were often referred to as being "sterile" or having "testicular failure." We start to use stem cell in treatment of such patients by injecting the stem cell at the testis and the testicular artery in one group and at the testis only in other group