wth does “NARTH” stand for? Sounds like a troll...
A quick search on Clusty (shameless plug for anybody but gugle) reveals “National Association for Research & Therapy on Homosexuality.”
I first ran across some of this evidence in a college textbook on religious cults, of all places. It turns out that some cults such as the Moonies, that object to homosexuality, were able to successfully re-orient former homosexuals into a heterosexual orientation until they were indistinguishable from always-heterosexuals in the studies conducted by the scientist making the study. (Cf. Dr. Marc Galanter's book Cults: Faith, Coercion, Healing, if I recall correctly.)