Most SNP-populated genes related to male infertility include HLA-DQB1 (20 SNPs), HLA-DRB1 (15 SNPs), MTHFR (10 SNPs), BRCA2 (9 SNPs), ACE (8 SNPs), CFTR (6 SNPs), CDH1 (6 SNPs), SRD5A2 (6 SNPs), HLA-DQA1 (5 SNPs) and MMP9 (5 SNPs). This evidence concerns the gene MMP9 and male infertility.