Sexology is defined as the systematic study of human sexuality. It covers many if not all aspects of human sexuality, including the attempt to identify what is seen as "normal sexuality" as well as all its different and varied forms. Like other cross-discipline fields, Sexology uses a multitude of techniques and parameters from a multitude of scientific and medical fields, like biology, medicine, psychology, statistics, epidemiology, sociology, anthropology, and sometimes criminology – to study its subject matter and individuals presenting with illness and problems. Sexology also focuses on the study of human sexual development and the development of sexual relationships as well as the mechanics of sexual intercourse and sexual malfunction. Branches of Sexology also study and treat some of the darker sides of human behavior and sexual pathologies such as sex addiction and child sexual abuse.