[Sperm DNA damage and male infertility].

Conventional semen analysis is a poor predictor of reproductive outcome. There is a lot of evidence that sperm DNA fragmentation tests can differentiate fertile from infertile men. DNA damage can be due to intrinsic (e.g., protamine deficiency), or extrinsic factors (e.g., tobacco smoking, infections, testicular hyperthermia, varicocele). Seminal plasma leucocytes generate excess free oxygen radicals and can cause sperm DNA fragmentation. Couples in whom the husband has a high DNA damage have low potential to a natural pregnancy. Sperm DNA damage is also associated with a lower pregnancy rate and an increase of pregnancy loss in assisted reproduction treatments.