There is no credible scientific organization that supports the concept of conversion therapy for members of the LGBT community.  Most are stridently against it.   Those in support of it are simply bigoted against the LGBT community and they must be recognized as such.  Allowing conversion therapy because a therapist wants to practice outside the guidelines of any professional organization would be the same as allowing an oncologist to treat a cancer patient with laetrile.   It is harmful and it is unsupported by any scientific studies.  It must be banned.