en Original Article Original Article Fertilization involves direct interaction of the sperm and oocyte, fusion of the cell membranes and :::::union::::: of male and female gamete genomes. The completion of this process and subsequent embryo development depend in part on the inherent integrity of the sperm DNA. Sperm genome quality has been emphasized for several years as playing a major role in early embryogenesis. There is clinical evidence showing that human sperm DNA damage may adversely affect reproductive outcomes and that spermatozoa of infertile men possess substantially more DNA damage than do spermatozoa of fertile men. Testing DNA integrity may help selecting spermatozoa with intact DNA or with the least amount of DNA damage for use in assisted reproductive techniques (ARTs). This review will focus on how sperm DNA is organized, what causes sperm DNA damage and what impact this damage may have on reproductive outcome. Fertilization, Sperm DNA damage, Assisted reproductive technique (ART). 137 150 http://ijrm.ir/browse.php?a_code=A-10-549-302&slc_lang=en&sid=1 Mohamed Youssry No Department of Obstetrics and Gynecology, University of Alexandria, Alexandria, Egypt Batuhan Ozmen No Department of Obstetrics and Gynecology, University of Ankara, Ankara, Turkey Yasser Orief No Department of Obstetrics and Gynecology, University of Alexandria, Alexandria, Egypt Khaled Zohni No Medical Sciences Division, Reproduction Unit, National Research Center, Egypt Safaa Al-Hasani sf_alhasani@hotmail.com Yes Department of Obstetrics and Gynecology, University of Schleswig – Holstein, Luebeck, Germany