Many people believe that miscarriage is a woman’s problem and has nothing to do with men. Is this really the case? Actually not, bad sperm in men can also lead to abortion and infertility. So in case of abortion or miscarriage, it is important to check not only the female partner but also the male partner. Among them, high sperm DNA fragmentation index (DFI) may be the culprit of many “unexplained” miscarriage couples and infertility. An abnormally high DFI reflects the integrity of the genetic material of the sperm and can have a negative impact on fertility, causing infertility and recurrent miscarriages. Who needs this test? (1) Spouses with recurrent spontaneous miscarriage and embryonic abortion; (2) Patients with male infertility who have been unsuccessful in using assisted reproductive technology to assist conception; (3) Patients with idiopathic male infertility (except azoospermia) who exclude female factors; (4) Patients with male partner ≥ 40 years of age who are to undergo assisted reproductive technology to assist conception; (5) Patients who have been working or living for a long time in high temperature, radiation, toxic chemicals, heavy tobacco and alcohol addiction, etc. (5) people who have been working or living in high temperature, radiation, toxic chemicals, heavy smoking and alcohol consumption for a long time (e.g. cooks, machine room workers, etc.); (6) people who have undergone voluntary preconception eugenics examination. If the male partner has a high DFI, what should we do? 1.Medication Antioxidants can stop the production of reactive oxygen species and remove excessive reactive oxygen species. It helps to improve semen quality, maintain and reduce sperm DNA damage. Commonly used antioxidants mainly include coenzyme Q10, glutathione, carotenoids, vitamin C, vitamin E and some herbal ingredients. In addition oxygen free radicals produced by leukocytes after reproductive tract infection can damage sperm DNA integrity, and treatment with antibiotics can also reduce the proportion of sperm DNA fragmentation. 2.Surgical treatment Varicocele is a common disease of the uro-male reproductive system and one of the common causes of male infertility. Varicocele can lead to a decrease in sperm quality and testosterone secretion through mechanisms such as local tissue hypoxia, increased temperature and metabolic waste accumulation in the testes, all of which lead to a decrease in male fertility. For infertile patients with varicocele accompanied by oligospermia or high DFI, microsurgical treatment can be used to improve semen quality and reduce sperm DNA damage. For patients with infertility who cannot achieve the expected results with both drug and surgical treatments, assisted reproductive technology is currently the most common and effective treatment method. choosing ICSI (second generation IVF) treatment for high DFI may be better than conventional IVF and more helpful in overcoming the poor pregnancy outcomes associated with high DFI. It has also been shown that ICSI treatment using testicular spermatozoa in patients with severe oligo-, hypospermia with multiple unsuccessful ICSI treatments, repeated implantation failures and recurrent miscarriages can reduce sperm DNA damage, resulting in better pregnancy outcomes. The methods applied to improve and treat DFI are still very limited, not always very effective, and only effective for some infertile couples. Adequate preparation should be made before pregnancy preparation. In addition to maintaining healthy and good lifestyle habits and early fertility, early IVF treatment will be more beneficial to improve pregnancy rate.