This book discusses the role of oxidative stress in human reproduction with a focus on men’s health. The physiological roles of reactive oxygen species (ROS) in male fertility are the focus in this book. This topic is important because oxidative stress is a result of the imbalance between ROS and antioxidants in the body which may lead to sperm damage (DNA or count), deformity, and eventually, male infertility. Therefore, for a better understanding of the molecular mechanisms related to male genotoxicity and its regulation in infertility, this book provides an up-to-date view on the impact of oxidative stress factors in male reproduction . The main aim of this book is to collect a series of research articles and reviews from a diverse group of scientists to share their research work on the role of ROS or oxidative stress in physiological and pathological states in relation to (in)fertility in the male. This book presents various state-of-the-art chapters of the recent progress in the field of cellular toxicology and clinical manifestations of various issues related to men’s health and fertility. Topics include cell signaling, DNA damage and infertility, the pathophysiology of disease instigation and distribution, immune toxicity and prevention.