Gunes S, et al. - This trial probed into the methylation patterns of the DNA mismatch repair genes MLH1 and MSH2, in oligozoospermic males. The oligozoospermic patients reported more methylation of MLH1 than normozoospermic patients. In order to ascertain if the hypermethylation of the MLH1 promoter played a role in repairing relevant mismatches of sperm DNA strands in idiopathic oligozoospermia, additional analyses were required.