As a traditional engine of plot, sex has been central in the literatures of the West from the beginning. It is the direct cause of actions later taken, as in Homer's Iliad (circa 850BC) and many of the classic detective novels of the 20th century; it is the subject matter of the Story, as in Story Cycles like Giovanni Boccaccio's Decameron (before 1353), or in the love-romances of this century; it is the hidden substance that governs the surface shenanigans of the courtly Romance, or the machinations that irradiate the Matter behind Myths of Origin (>>> Arthur), or the seductions of Supernatural Fiction, where a sexual charge between the supernatural realm and this world is central, whether overt or hidden, justified or seen as miscegenation. The underlying language of Horror, too, is suffused with images and gestures of sexual violation, and is the main carrier into the 20th century of the linkage between sex and the violating Other typical of Gothic Fantasy. However, though Fantasy also depends ultimately for its energy on sexual flux, the genre has traditionally avoided plots overtly based on sexual relations.
In recent years, of course, the politics of sex have affected fantasy, like all other popular genres. Before recent decades, any woman capable of acting a protagonist's role would likely be seen as appalling at the very least; more probably, she would be represented as a victim of Possession, or an Avatar of the dark side of the Goddess (>>> Lamia; She). Exceptions – like C L Moore's tomboy Shambleau, whose Planetary-Romance venue was typical of that category in providing a licence for female excesses – were rare. But autonomous females now proliferate; in modern Sword and Sorcery, for example, a mercenary is almost as likely to be a woman as a man (>>> Temporal Adventuress), and although most full-fantasy narratives still have male protagonists exceptions are numerous.
Overt depictions of the sexual act are relatively uncommon in Genre Fantasy, though they are increasingly part of the lingua franca of supernatural fiction (notably concerning Vampires) and horror. [JC]