Editorial [ Male Contraception Guest Editor: C. Yan Cheng ]

When I was a graduate student in the late 1970s, much of the study that was conducted on male reproductive biology which formed the basis of male contraceptive research focused on three main areas: (i) endocrine regulation at the level of the hypothalamic-pituitary-testicular axis, (ii) morphological studies to delineate the events of sperm maturation in the testis and epididymis, and (iii) the biology of spermatozoa (e.g., sperm-specific antigens for vaccine development) and sperm-egg interactions. Some efforts were also made to use extracts of natural products (e.g., gossypol from cotton seeds), chemicals (e.g., GnRH antagonists and/or agonists, lonidamine) and several others for male contraception. At that time, I was studying sperm function in the human. However, developments in biochemistry, medicinal chemistry, and cell and molecular biology in the next two decades have drastically transformed the approaches used to study male reproductive biology and contraceptive research. With these powerful research techniques in hand, investigators have tackled many basic questions which would not have been possible just a decade ago. In this Special Issue entitled: “Male Contraception” published in Immunology, Endocrine & Metabolic Agents in Medicinal Chemistry, I have attempted to bring forth a few selected topics written by investigators in the field. These articles have introduced some thought-provoking concepts, which I felt might interest both young and senior investigators. Due to space limitations, I was not able to cover all areas of research interest in the field, such as recent developments in the use of testosterone or testosterone and progestin combinations to induce reversible infertility in men. Nonetheless, I have attempted to provide a balanced treatment on the topic of “Male Contraception” by recruiting a diverse group of investigators to contribute to this issue, making it a timely collection of review articles for reproductive biologists and investigators in male contraceptive research. While we have seen a significant drop in funding in contraceptive research in recent years, enthusiasm among scientists has not diminished. I hope that this Special Issue will further spark interest among investigators in the field. I wish to thank my colleagues who have taken their time to write an article for this Special Issue. I am also grateful to Bentham Science who has helped me to assemble this issue from its inception to its publication.