Evelyn Hooker

Evelyn Hooker (September 2, 1907–November 18, 1996) was an American psychologist most notable for her 1957 paper "The Adjustment of the Male Overt Homosexual" in which she administered several psychological tests to groups of self-identified homosexuals and heterosexuals and asked experts to identify the homosexuals. The experiment, which other researchers subsequently repeated, demonstrates that homosexuality is not a mental disorder as there was no detectable difference between homosexual and heterosexual men in terms of mental adjustment.

Her work exposed a false correlation between homosexuality and mental illness that had formed the basis of scientific classification of homosexuality as a disorder, by avoiding the use of a sample group that contained homosexual men with a history of treatment for mental illness. It is of critical importance in refuting cultural heterosexism because it shows that homosexuality is not developmentally inferior to heterosexuality. As homosexuality is not an illness, bias against it is irrational from a scientific point of view.