USP9Y and Azoospermia: Deletions in the azoospermia factor region known as azoospermia factor a (AZFa), azoospermia factor b (AZFb), and azoospermia factor c (AZFc) loci independently or together which are situated on the Y chromosome cause a disturbance and alteration that are linked to either a reduction in sperm count, known as oligozoospermia, or the absence of sperm cells in the semen sample, referred to as azoospermia.