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 social criticism.
Sexologists apply tools from several academic fields, such as anthropology, biology, medicine, psychology, epidemiology, sociology, and criminology. Topics of study include sexual development (puberty), sexual orientation, gender identity, sexual relationships, sexual activities, paraphilias, and 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 those with mental or physical disabilities. The sexological study of sexual dysfunctions and disorders, including erectile dysfunction and anorgasmia, are also mainstays.
Sex manuals have existed since antiquity, such as Ovid's Ars Amatoria, the Kama Sutra of Vatsyayana, the Ananga Ranga, and The Perfumed Garden for the Soul's Recreation. De la prostitution dans la ville de Paris (Prostitution in the City of Paris), an early 1830s study on 3,558 registered prostitutes in Paris, written by Alexander Jean Baptiste Parent-Duchatelet (published in 1837, a year after he died), has been called the first work of modern sex research. In England, James Graham was an early sexologist who lectured on topics such as the process of sex and conception.
The scientific study of sexual behavior in human beings began in the 19th century with Heinrich Kaan, whose book Psychopathia Sexualis (1844) Michel Foucault describes as marking "the date of birth, or in any case the date of the emergence of sexuality and sexual aberrations in the psychiatric field." The term sexology was coined for the first time in the United States by Elizabeth Osgood Goodrich Willard in 1867.