early twentieth century Germany experiments were carried out in which homosexual men were subjected to unilateral orchiectomy and testicles of heterosexual men were transplanted. These operations were a complete failure. Surgical castration of homosexual men was widespread in Europe in the first half of the twentieth century and was also practiced in the United States. SS leader Heinrich Himmler ordered homosexual men to be sent to concentration camps because he did not consider a time-limited prison sentence was sufficient to eliminate homosexuality. Although theoretically voluntary, some homosexuals were subject to severe pressure and coercion to agree to castration. There was no age limit; some boys as young as 16 were castrated. Those who agreed to castration after a Paragraph 175 conviction were exempted from being transferred to a concentration camp after completing their legal sentence. Some concentration camp prisoners were also subjected to castration. An estimated 400 to 800 men were castrated. Endocrinologist Carl Vaernet attempted to change homosexual concentration camp prisoners' sexual orientations by implanting a pellet that released testosterone. Most of the victims, non-consenting prisoners at Buchenwald, died shortly thereafter. An unknown number of men were castrated in West Germany and chemical castration was used in other Western countries, notably against Alan Turing in the United Kingdom. Ex-gay/ex-trans ministry Some sources describe ex-gay and ex-trans ministries as a form of conversion therapy, while others state that ex-gay organizations and conversion therapy are distinct methods of attempting to convert gay people to heterosexuality. The umbrella organization Exodus International in the United States ceased activities in June 2013, and the three member board issued a statement which repudiated its aims and apologized for the harm their pursuit has caused to LGBT people. Ex-gay/ex-trans organizations often overlap and portray being trans as inherently sinful or against God's design, or pathologize gender variance as due to trauma, social contagion, or "gender ideology." Hypnosis Hypnosis was used in conversion therapy since the 19th century by Richard von Krafft-Ebing and Albert von Schrenck-Notzing. In 1967, Canadian psychiatrist Peter Roper published a case study of treating 15 homosexuals (some of which would probably be considered bisexuals by modern standards) with hypnosis. Allegedly, 8 showed "marked improvement" (they reportedly lost sexual attraction towards the same sex altogether), 4 mild improvements (decrease of "homosexual tendencies"), and 3 no improvement after hypnotic treatment; he concluded that "hypnosis may well produce more satisfactory results than those obtainable by other