The American Psychiatric Association and the American Psychological Association have suggested for many years now that there is significant empirical evidence supporting the claim that homosexuality is a normal variant of human sexual orientation as opposed to a mental disorder. This paper summarizes and analyzes that purported scientific evidence and explains that much (if not all) of the evidence is irrelevant and does not support the homosexuality-is-not-a-mental-disorder claim. As a result of their deficiencies and arbitrariness, the credibility those two groups that are typically deemed authoritative and trustworthy is called into question. Lay summary: At one time, homosexuality was considered to be mentally disordered. Since the 1970s, however, major medical associations in the U.S. have labeled homosexuality as a normal counterpart of heterosexuality. Those medical associations have proposed that their homosexuality-is-normal claim is based on "scientific evidence." This article critically reviews that "scientific evidence" and finds that much of their literature does not support the claim that homosexuality is normal. This article suggests that instead of supporting their claim with scientific evidence, those major medical associations arbitrarily label homosexuality as normal.
Keywords: Adjustment; Empirical evidence; Homosexuality; Lawrence v. Texas; Mental disorder; Same-sex attraction; Scientific evidence; United States v. Windsor.