Based on copy number estimates of DAZ and CDY1 genes, it is observed that only those men with two DAZ and one CDY1 copy deleted will have azoospermia or oligozoospermia, retention of any one of these genes will be almost always be associated with normozoospermia [139, 140, 143, 145, 149]. The gene discussed is CDY1; the disease is Azoospermia.