There are several types of damage that can be found in the male gamete. Genetic damage in spermatozoa can originate during spermatogenesis, or it can originate during transit in both male and female genital tracts. Damage can also be due to ageing, environmental or iatrogenic conditions, as well as to the protocols to cryopreserve and to select spermatozoa in assisted reproduction techniques. The purpose of this book is to provide a comprehensive resource for all possible DNA damages in sperm, the relation to fertility and infertility, and possible transgenerational heritable effects.