The researchers hypothesized that nonobstructive azoospermia might be associated with a reduction OF SSCs in seminiferous tubules as compared with obstructive azoospermia. Testicular sperm specimens that had been previously extracted from azoospermic patients will be paraffin embedded and stained with anti GPR-125. After antigen retrieval, the sections will be incubated with rabbit anti GPR125 followed by Cy3-conjugated anti rabbit secondary antibodies. Those found to be SSCs will be counted using light microscopy, and compared between patients with obstructive (n=11) and non-obstructive azoospermia (n=9).