In this book the authors present current research in the study of spermatozoa. This compilation focuses on the biology, motility and function and chromosomal abnormalities of spermatozoa. Topics discussed are the epigenetic mechanisms in mammalian male germline; biological characteristics of sperm in two oyster species; sub-cellular dynamics occurring during capacitation of mammalian spermatozoa; new perspectives on the study of prion and prion-like proteins; meiotic segregation studies in spermatozoa of males carrying a structural chromosome abnormality; testicular germ cell apoptosis during orchitis; the influence of leukocytospermia on semen parameters; and spermatozoa motility and morphology.