Our research was designed to verify the relationship between male infertility, basic semen characteristics (with respect to detailed sperm morphology), sperm DNA fragmentation (SDF), oxidation-reduction potential in semen (ORP), and leukocytospermia. The obtained results showed that infertile groups (with or without leukocytospermia) had significantly lower basic semen characteristics and higher SDF, raw ORP, and static ORP (sORP) than fertile controls. The thresholds of 13% SDF (AUC = 0.733) and 1.40 sORP (AUC = 0.857) were predictive values for discriminating infertile from fertile men. In infertile groups, a higher prevalence and risk for >13% SDF and >1.40 sORP were revealed. Unexpectedly, leukocytospermic subjects had lower sORP, prevalence, and risk for >1.40 sORP than leukocytospermic-negative men. These groups did not differ in SDF and raw ORP. Both SDF and sORP negatively correlated with basic semen parameters but positively correlated with sperm head and midpiece defects. sORP positively correlated with sperm tail defects, immature sperm cells with excess residual cytoplasm, and SDF. In turn, raw ORP negatively correlated with sperm count but positively correlated with SDF and sORP. These findings indicate that (1) there is a relationship between male infertility, SDF, and OS in semen; (2) in infertile men, there is a clinically significant risk of SDF and OS irrespective of leukocytospermia; and (3) the assessment of SDF and oxidative stress should be independent of leukocytospermia.
