ProCon.org is a nonprofit that works hard to provide unbiased information on both sides of controversial topics; it’s widely perceived as doing a good job at being nonpartisan, and is relied on by a number of national governments, the American Library Association, and many news outlets. It even lists the flaws in its own methods. Some controversial issues, of course, like evolution, simply divide where reality ends and wishful thinking picks up. Still, to see the poor quality of what the other side has mustered by way of evidence can be instructive.
Here’s its page on whether sexual orientation can be changed. The naysayers include the Surgeon General, the American Psychological Association, and the American Psychiatric Association. Those that ProCon found speaking in favor were NARTH, the Catholic Medical Association, and Robert Spitzer from Columbia. [The Spitzer study cited was controversial, and TWO spoke to him several years ago, at which point he clarified the problems with his own study while condemning dishonest religious groups like NARTH and Focus on the Family for misusing his research in their anti-gay hate campaigns.]
More pros and cons from ProCon.org on questions surrounding changing sexual orientation are here.