For example, deletion of SPINK2, an azoospermia-associated gene, caused oligo-teratozoospermia in mice (30), and knockout of Wdr63, a gene mutated in both multiple morphological abnormalities of the sperm flagella and NOA patients, led to infertility with decreased sperm number and abnormal flagellar morphology in mice (31). The gene discussed is SPINK2; the disease is Infertility.