I don't got any evidence, but i believe it is a matter of time till scientist are able to tackle stuttering and fix it . I mean the future looks bright in general , Advances are being made in all sorts of scientific field thanks to AI, right now Scientists are developing cures for HIV , and many other diseases there is even some clinical trials to reverse blindness ,all of these are happening in the span of a year imagine what will come in the next 5-10 years