Sexology is the scientific study of human sexuality, including human sexual interests, behaviors and functions. The term sexology does not generally refer to the non-scientific study of sexuality, such as political science or social criticism. Sexologists apply tools from several academic fields, such as biology, medicine, psychology, epidemiology, sociology, and criminology. Topics of study include sexual development (puberty), sexual orientation, gender identity, sexual relationships, sexual activities, paraphilias, atypical sexual interests. It also includes the study of sexuality across the lifespan, including child sexuality, puberty, adolescent sexuality, and sexuality among the elderly. Sexology also spans sexuality among the mentally and/or physically disabled. The sexological study of sexual dysfunctions and disorders, including erectile dysfunction, anorgasmia, and pedophilia, are also mainstays.