In the fall of 1977, Andy Warhol began work on two new series of artworks which would become known as Torsos and Sex Parts. While the Torsos paintings would quickly be praised for following in the “high art” style of classical nudes, the Sex Parts series from which Torsos was borne blurred the line between art and pornography. In creating the artworks, Warhol was probably inspired by classical nudes and erotic art which have been depicted throughout history. Sexuality in artwork can be found as early as 35,000 BC in central Europe with the erotic sculptures of the Venus of Hohle Fels and later the Venus of Willendorfstatuettes, all of which have enlarged breasts and well-defined genitalia.
Read more at warhol.org: http://www.warhol.org/webcalendar/event.aspx?id=2056#ixzz234uSDk8b