In contemporary usage, “sexuality” refers to sexual orientation or the direction of an individual’s desire. It is closely entwined with but also separable from biological sex (male, female, intersex) and gender expression (masculinity, femininity, transgender). The categories of heterosexuality, homosexuality, and bisexuality are based on a binary sex/gender system and are defined by an individual’s object choice. Prior to this modern sense of sexuality as denoting erotic preferences and tastes, however, engaging in certain sexual acts did not necessarily entail definite sexual identities. It is not until the nineteenth and twentieth centuries through the work of sexologists, psychoanalysts, and state administrators that sexuality was gradually differentiated from sex and took on the psychological and emotional valences that it currently possesses, drawing into its orbit connotations of desire and attraction, fantasy and pleasure (Canaday 2009; Davidson 2001; Oosterhuis 2000).