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. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771012/