On the history of biological theories of homosexuality.

Biological theories of homosexuality fit into the discourse on reproduction and sexuality that began in the nineteenth century. They arose in the context of the early homosexual rights movement, with its claim for natural rights, and the psychiatric discussions about sexual perversions. With the classification of homosexuality as a distinct category, homosexuals were excluded from the "normal". Biological theories of homosexuality were attempts not only to explain its causes, but also to maintain the exclusion of homosexuals as the "other". Biological explanations can be categorized as genetic, constitutional, endocrinological, and ethological. On the one hand, biological theories were used in the struggle for homosexual rights. On the other hand, they were used to "cure"e homosexuals. Every theory led to a specific therapy. This paper points out the roots of this thinking, traces the development of various theories, and shows the utilization of biological theories in treating homosexuality.