The results demonstrated that thefrequencies of CC/GA-combined genotypes of C-1562T MMP-9 and G-1575A MMP-2 gene polymorphismshad a significant difference between fertileand infertile men (P=0.032, χ2=4.6, df=1) (Table 4).We also analyzed the synergistic effect of allelesC-1562T MMP-9 and G-1575A MMP-2 gene polymorphismson male infertility (Table 5). Here, MMP9 is linked to male infertility.