Additionally, sperm DNA fragmentation was positively correlated with the level of malondialdehyde (MDA—biomarker of lipid peroxidation: r = 0.735) and negatively correlated with the level of superoxide dismutase (r = −0.781), catalase (r = −0.686) and glutathione peroxidase (r = −0.721) in the total study group (men with or without varicoceles) [24]. Here, CAT is linked to varicocele.