Evelyn Hooker (née Gentry, 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 male homosexuals and heterosexuals and asked experts to identify the homosexuals and rate their mental health. The experiment, which other researchers subsequently repeated, argues that homosexuality is not a mental disorder, as there was no detectable difference between homosexual and heterosexual men in terms of mental adjustment.