Fritz Klein (sex researcher)

Fred "Fritz" Klein (December 27, 1932 – May 24, 2006) was an Austrian-born American psychiatrist and sex researcher who studied bisexuals and their relationships. He was an author and editor, as well as the developer of the Klein Sexual Orientation Grid, a scale that measures an individual's sexual orientation. Klein believed that sexual orientation could change over the course of a lifetime and that researchers underestimated the number of men that had sexual interactions with both sexes. Fritz Klein founded the American Institute of Bisexuality in 1998, which is continuing his work by sponsoring bisexual-inclusive sex research, educating the general public on sexuality, and promoting bisexual culture and community.