Viennese endocrinologist who transplanted testicles from straight men into gay men in attempts to change their sexual orientation

Sigmund Freud

Main article: Sigmund Freud's views on homosexuality

Freud (1856–1939) was skeptical of the possibility of therapeutic conversion.

Sigmund Freud was a physician and the founder of psychoanalysis. Freud stated that homosexuality could sometimes be removed through hypnotic suggestion,^[24] and was influenced by Eugen Steinach, a Viennese endocrinologist who transplanted testicles from straight men into gay men in attempts to change their sexual orientation,^[25] stating that his research had “thrown a strong light on the organic determinants of homo-eroticism”.^[26] Freud cautioned that Steinach's operations would not necessarily make possible a therapy that could be generally applied, arguing that such transplant procedures would be effective in changing homosexuality in men only in cases in which it was strongly associated with physical characteristics typical of women, and that probably no similar therapy could be applied to lesbianism.^[27][28] In fact Steinach’s method was doomed to failure because the immune system rejects transplanted glands, and was eventually exposed as ineffective and often harmful.^[29]
Freud‘s main discussion of female homosexuality was the 1920 paper “The Psychogenesis of a Case of Homosexuality in a Woman“, which described his analysis of a young woman who had entered therapy because her parents were concerned that she was a lesbian. Her father wanted this condition changed. In Freud‘s view, the prognosis was unfavourable because of the circumstances under which she entered therapy, and because homosexuality was not an illness or neurotic conflict. Freud wrote that changing homosexuality was difficult and possible only under unusually favourable conditions, observing that “in general to undertake to convert a fully developed homosexual into a heterosexual does not offer much more prospect of success than the reverse.”^[30] Success meant making heterosexual feeling possible, not eliminating homosexual feelings.^[31]
Gay people could seldom be convinced that heterosexual sex would provide them with the same pleasure they derived from homosexual sex. Patients often wanted to become heterosexual for reasons Freud considered superficial, including fear of social disapproval, an insufficient motive for change. Some might have no real desire to become heterosexual, seeking treatment only to convince themselves that they had done everything possible to change, leaving them free to return to homosexuality after the failure they expected.^[32][33][34]
In 1935, a mother asked Freud to treat her son. Freud replied in a letter that later became famous:^[35]

"I gather from your letter that your son is a homosexual. [...] it is nothing to be ashamed of, no vice, no degradation; it cannot be classified as an illness; we consider it to be a variation of the sexual function, produced by a certain arrest of sexual development. [...] By asking me if I can help [your son], you mean, I suppose, if I can abolish homosexuality and make normal heterosexuality take its place. The answer is, in a general way we cannot promise to achieve it. In a certain number of cases we succeed in developing the blighted germs of heterosexual tendencies, which are present in every homosexual; in the majority of cases it is no more possible. It is a question of the quality and the age of the individual. The result of treatment cannot be predicted."^[36]