Spermatozoa are susceptible to damage from excess reactive oxygen species (ROS) and oxidative stress. The reason for this is that spermatozoa, due to their low cytoplasm, have a reduced antioxidant content. In addition, polyunsaturated fatty acids in the sperm membrane can undergo lipid peroxidation by ROS.
Lipid peroxidation leads to a loss of fluidity in the sperm membrane, which affects its motility and its ability to bind to the oocyte. In addition, oxidative stress also leads to sperm DNA damage and fragmentation.