Kinsey Reports
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 to 6. 0 means the person tested is exclusively heterosexual. A person scoring 6 is exclusively homosexual. In the Kinsey Reports, an extra grade was used for asexuality. The scale  was first published in Sexual Behavior in the Human Male (1948). It was also  important in the complementary work Sexual Behavior in the Human Female (1953).