Sexology is the interdisciplinary field that studies human sexual behaviour, orientation, function, development, and diversity. It was born in late-nineteenth-century Europe and developed through the twentieth century at the crossing of medicine, psychology, sociology, and anthropology.

The birth of modern sexology: late-nineteenth-century Europe

The most important starting point of modern sexology is Psychopathia Sexualis (1886) by the German psychiatrist Richard von Krafft-Ebing. The work was the first large-scale study to record systematically a range of “sexual deviations,” and it defined and popularised terms such as fetishism, masochism, sadism, and homosexuality. Krafft-Ebing’s approach aimed chiefly at the description of “pathology” and carried a side that reinforced the normative sexual views of the time.

The British physician Havelock Ellis wrote Studies in the Psychology of Sex (1897-1928), treating homosexuality, female sexual response, and sexual deviation more neutrally and scholarly. Ellis held homosexuality to be an inborn natural variation rather than crime or moral degeneration, a departure from the mainstream of his time.

Freud and psychoanalysis

Sigmund Freud (1856-1939) presented, in Three Essays on the Theory of Sexuality (1905), the concepts of infantile sexuality, libido, and varied stages of sexual development. Freud’s theory had a large cultural impact through its claim that sexual desire is a fundamental motive of human behaviour, but much of it was not supported by later empirical research, and his scholarly legacy continues to receive a complex evaluation.

America: the Kinsey Reports

Alfred Kinsey (1894-1956), a zoologist turned sexologist, conducted a large-scale survey of sexual behaviour among thousands of Americans in the 1940s. Published as Sexual Behavior in the Human Male (1948) and Sexual Behavior in the Human Female (1953), the Kinsey Reports gave statistical prevalence figures for behaviours then held taboo, including homosexual experience, extramarital intercourse, and masturbation frequency, and caused a sensation. The “Kinsey scale” he proposed (a seven-point range from 0, exclusively heterosexual, to 6, exclusively homosexual) popularised the idea that sexual orientation exists as a continuous spectrum rather than a binary opposition.

Masters and Johnson and the study of sexual response

William Masters and Virginia Johnson (co-authors of Human Sexual Response, 1966, and Human Sexual Inadequacy, 1970) published the first systematic study to observe and measure physiological responses during sexual activity directly in the laboratory. Their four-stage model of sexual response (excitement, plateau, orgasm, resolution) is established as basic knowledge of present-day sexology.

Present-day sexology

Present-day sexology works increasingly with neuroscience, genetics, evolutionary biology, sociology, and cultural anthropology, and brain-imaging research such as fMRI is used to clarify the neural basis of sexual response and orientation. The revisions of the DSM (the depathologisation of homosexuality in 1973 and the distinction of paraphilia from disorder in 2013) are typical examples of the influence of sexological findings on social and medical practice.

In Japan, Western sexology was translated and received in the Meiji and Taisho periods as the “study of sexual desire,” and the concepts of “perverse desire” and “sexual deviation” spread. Distinctly Japanese sexological inquiry of the period includes Sawada Junjiro’s On Perverse Sexual Desire (1913).

See also

• History of venereal disease
• Libido
• Paraphilia