Although sex hormones are generally thought to be involved mainly in reproductive functions, they are also involved in antioxidant mechanisms, in cardiovascular and brain functions, and in incidence of some diseases. In this book, the authors present current research in the study of the development, regulation and disorders relating to sex hormones. Topics discussed include sex hormones are their implication in metabolic disease, and neurological disorders such as schizophrenia, Alzheimer's disease, depression and migraine, the non-reproductive effects of sex hormones and the cardiovascular system, the sources and presence of steroid sex hormones in freshwater ecosystems and sex hormone receptors and epigenetics in breast cancer.