Sexology refers to the scientific study of human sexuality and its goal is to classify human sexual behavior. It considers sexual activity a natural biological phenomenon and thus decouples sex from moral and religious authority. It views sexuality through the prism of science. However, the status of sexology as true science has been questioned frequently because of its constantly changing methodologies and overlapping disciplines.
The modern concept of sexology has to be distinguished from the older concept of erotology. Erotological writings like Vatsayana's Kama Sutra and its Western counterparts guide the reader to subjective experiences, while sexological writings focus on the objective insight. The scientific study of sex and sexuality can be traced back to the classical Greek period when Hippocrates, Plato and Aristotle are considered to be the forefathers of sexual research because they offered the first elaborate theories regarding sexuality issues. In Rome, Greek physicians such as Soranus and Galen further advanced and systematized ancient sexual knowledge, which later motivated Islamic scholars to examine sexual questions.
However, the rise of sexology as a separate science occurred in the late 19th century in the disciplines of psychoanalysis and anthropological research. The development of sexology is closely linked to the major cultural movements of modernity such as the rise of a sexual liberalism that opposed Victorian morality, asserted heterosexual female desire and challenged gender roles. The rise of sexology in Europe around the turn of the 20th century was indirectly triggered by the criminalization of prostitution and the transmission of venereal diseases in urban areas. The eugenics movement, which sought to enhance breeding in order to improve the species, is also believed to be responsible for the rise of sexology.
The new concept of a science of sexuality was proposed by the dermatologist Iwan Bloch (1872-1922) who also coined a new term for it - sexualwissenschaft or sexology. Bloch founded the first professional sexology association in 1913 in Berlin. Six years later, Magnus Hirschfeld (1868-1935) founded the first sexological institute which had an important archive and library. Hirschfeld and Havelock Ellis (1859-1939) are regarded as the most prominent figures of early sexology, even though the works of Bloch, Sigmund Freud (1856-1939), Albert Moll (1862-1939) and Max Marcuse (1877-1963) were deemed to be highly influential. The seven-volume Studies in the Psychology of Sex, written by Ellis and published in 1940, addressed a wide range of sexual behaviors. Hirschfeld's best-known texts are Transvesitten, published in 1941, in which he coined the term transvestism and Sexual Pathology: A Study of Derangements of the Sexual Instincts (1940).
Alfred C. Kinsey (1894-1956) helped the science of sexuality become popular in the late 1940s by conducting detailed interviews with more than 18,000 people about their sexual practices and experiences. Kinsey, with his training and experience as a zoologist, was well suited for the task of taking a large-scale, strictly empirical survey of actual sexual behavior in the United States. His findings, which appeared in Sexual Behavior in the Human Male (1948) and Sexual Behavior in the Human Female (1953), caused a major debate on the American views of sexual practice. Other prominent sexologists of the second half of the 20th century include William Masters, Virginia Johnson, John Gagnon, William Simon and Helen Singer Kaplan.
Critics of sexology argue that it has many problems, ranging from its fractured nature and subject matter, which often causes offence. In addition, sexologists have complained that their work is described as "laughable" or "perverted." Kinsey faced difficulties in obtaining funding for his research during McCarthyism from the late 1940s to the late 1950s, showing how changing political and cultural attitudes towards sex can hamper research. Sexology is often criticized for overestimating the importance of scientific objectivity and for its strong reliance on its ties to the medical community.
Sexologists have also been accused of being unable to provide an explanation for the social and cultural forces at work in the construction of sex, gender and sexuality. Feminists, gays, lesbians, bisexuals and transgender groups and scholars have contested the biological determinism advocated by some sexologists. These groups claim that sexual and gender variations should be viewed as a social formation rather than as individual defects.