Sigmund Freud,
Three Contributions to the Theory of Sex
(1905)
“ DEVIATION IN REFERENCE TO THE SEXUAL OBJECT The popular theory of the sexual impulse corresponds closely to the poetic fable of dividing the person into two halves—man and woman—who strive to become reunited through love. It is therefore very surprising to hear that there are men for whom the sexual object is not woman but man, and that there are women for whom it is not man but woman. Such persons are called contrary sexuals, or better, inverts; the condition, that of inversion. The number of such individuals is considerable though difficult of accurate determination. ”
