The increase in the Bcl-2 activity in those types of DNA defects may reflect their vital role in protection against apoptosis by interference with the mitochondrial apoptotic pathway [36], while its activity in the sample with normal chromatin condensation may indicate that sperm mitochondrial defect can exist without the existence of nuclear DNA damage and could be the cause of male infertility [37]. This evidence concerns the gene BCL2 and male infertility.