Robert L. Spitzer states that his 2001 study on sexual orientation change is invalid because he does not know if the subject were deceiving themselves or lying to him.
Truth Wins Out, "Dr. Robert Spitzer Retracts 'Ex-Gay' Study and Apologizes to the LGBT Community," Youtube, May 30, 2012
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[2:32] The basic problem with this study was that I asked a bunch of people who claim they had changed from homosexual to heterosexual. And I accepted what they said about their change. And I've been thinking about this study for many years, I felt that I needed to not only say that the study is not valid, but I thought I should also say to the gay community, I apologize for any harm I have done to them, because of the study and my initial interpretation. And I certainly apologize to any gay person who because of the study, entered into reparative therapy and wasted their time and energy doing that. . .I had no way really of knowing when I examined any particular subject, whether they really had changed or whether they were deceiving themselves, or even outright lying when they claimed that they had changed.
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