The Kinsey scale, also called the Heterosexual-Homosexual Rating Scale, attempts to describe a person's sexual experience or response 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).