kinsey scale
The Kinsey scale, also called the Heterosexual–Homosexual Rating Scale, is used in research to describe a person's sexual orientation based on one's experience or response at a given time. The scale typically ranges from 0, meaning exclusively heterosexual, to a 6, meaning exclusively homosexual. In both the male and female volumes of the Kinsey Reports, an additional grade, listed as "X", indicated "no socio-sexual contacts or reactions" (asexuality).