Coming from a faith tradition with a heartbreaking connection to conversion therapy, and now working with so many who have suffered through such therapies, and continue to suffer as a result of those therapies, I know for certain that conversion therapy is not only ineffective but also dangerous.
According to Dr. Jack Drescher of the American Psychiatric Association, "People spend a lot of time and money on these treatments that don't work... So many people report that they feel depressed, suicidal, anxious, and hopeless, those are not uncommon responses to a failed treatment" (ABC News). They blame themselves when they aren't cured or aren't able to fully suppress their attractions to the same gender.
Conversion therapy should be a banned practice for all individuals, but children should at the very least be protected against being forced into treatments which show no credible evidence of success and cause long-term harm to their mental health.