Taking the meaning of psychopathia sexualis literally from its origins in Greek, psyche + pathos, meaning disease; and Latin, sexus, meaning male or female, it connotes a "mental disease characterized by sexual perversion" (Mosby's Medical, Nursing and Allied Health Dictionary, 2002).
Indeed, we recognize that in order to conduct a scientific study of sex is linked to medical and social, not just individual moral repercussions. These became more apparent as urban spaces enabled semi-visible homosexual subcultures and other manifestations of "deviancy," providing many opportunities for sexual gratification away from its "legitimate" locus within marriage. By the late nineteenth century, several factors facilitated the emergence of a sexual science. These were a growing awareness of the serious consequences of venereal diseases and the role of accepted sexual mores (the "double standard") in disseminating them; anthropological reports destabilizing assumptions of one "natural" pattern of sexual behavior; and increasing refusal among homosexuals to accept stigmatization, with a search for validatory models; and the influence of Darwinism and evolutionary theory in which sexual selection played the central role (Hall, 2003).
Throughout history, studies about "unconventional sex" had been numerous. In the 1860s, Karl Heinrich Ulrichs, a German lawyer, argued from theories of embryological development that homosexuality was neither a crime nor a disease but an inborn condition whereby one individual might have characteristics of the other gender to the one externally apparent, leading to sexual desire for the same, rather than the other, sex. In the following decades, French psychologist Alfred Binet defined "fetishism" and Italian criminologist Cesare Lombroso's writings on the sexually deviant gained wide currency. However, it was German psychiatrist Richard von Krafft-Ebing, who coined the term psychopathia sexualis in his book with the same title in 1886, that catalogued a vast variety of deviations. Thus, recent scholarship recognized him as the one who pioneered the interest of sexual perversion. He listened to different clients and learned from the numerous people of good social position who consulted him.
Krafft-Ebing combined several prevailing views on "sexual inversion" and collected over 200 case studies in his famous Psychopathia Sexualis of "abnormal" or "pathological" individuals to support his theses. He claimed that "frequent abuses of the sexual organs (masturbation) or an inherited abnormal constitution of the nervous system" (quoted in Bullough, 1979, p. 11) produced a perversion of the sexual instinct and "unnatural practices" such as homosexuality. His views on homosexuality were directly related to his religious view that the purpose of sex was reproduction and, therefore, any other type of sexual activity was an "unnatural practice" (Bullough, 1979). Interestingly, the term homosexuality was first introduced to an English audience by one of Krafft-Ebing's translators, Charles Gilbert