We have a mass of negative evidence going back about a century. Meaning that clinical experience shows that therapy has not led to reported changes in sexual attraction.

The same effect was noted again starting in about the early 1990s when a new wave of sexual attraction change therapy began. Exodus International, for example.

What caused the major mental health association around the world to declare the practix unethical in adolescence was that the only firm association tied to the practice was a sharp increase in suicide attempts.