Since the ratio between PRM1 and PRM2 is constant in mature sperm (in mice ~60% PRM2), and alterations of this ratio are associated with sperm defects and infertility [48–50], we next tested if male mice harboring the Prm2Δc allele display alterations of the PRM1/PRM2 ratio. This evidence concerns the gene PRM1 and Infertility.