The Kinsey scale attempts to describe a person's sexual history or episodes of their sexual activity at a given time. It uses a scale from 0, meaning exclusively heterosexual, to 6, meaning exclusively homosexual. In both the Male and Female volumes of the Kinsey Reports, an additional grade, listed as "X", was used for asexuality. It was first published in Sexual Behavior in the Human Male (1948) by Alfred Kinsey, Wardell Pomeroy and others, and was also prominent in the complementary work Sexual Behavior in the Human Female (1953). __TOC__