text: Sperm DNA fragmentation appears to be an important factor in the cause of male infertility, since men with high DNA fragmentation levels have significantly lower odds of conceiving. Oxidative stress is the major cause of DNA fragmentation in spermatozoa.  A high level of the oxidative DNA damage 8-oxo-2'-deoxyguanosine is associated with abnormal spermatozoa and male infertility.