SOURCE: "The Theory of Sexual Inversion," in Sexual Inversion, 1897. Reprint by Arno Press, 1975, pp. 128-40.

When sexologist Havelock Ellis first published Sexual Inversion in 1897, his study became one of the standard authorities in English on the subject. Considered a highly scientific and generally sympathetic perspective for its time, Ellis's work presents the view that most homosexuals are the product of an inborn condition that inverts their gender identities, coupling male personalities with female bodies and vice versa. Although largely discredited among professionals today, Ellis's theory still resonates in popular stereotype, and many students of gay and lesbian history study it as an important document. In the following excerpt, Ellis explains his central theory.

. . . What is sexual inversion? Is it, as many would have us believe, an abominable acquired vice, to be stamped out by the prison? or is it, as a few assert, a beneficial variety of human...