That's not real evidence (one story of one person, non tested): A psychologist can never prove their theories. I'm referring to real proof. The scientific method has to be used... And these doctors want to later use experimental treatment plans and get big pharma kickbacks. This is not just an interesting conversation.. This is an attempt to get the permission to try all kinds of drugs (frankly they may not even agree on which experiment they want). All over the planet there are doctors experimenting secretly with no success. Anyway, it is known that some stutterers are more severe than others. One stutterer is not the same as the other. And if you say they can prove it (without drugging people or ruining their lives), then they should go ahead prove it. Making the declaration is not proof.