I never accepted the hypothesis of it being one’s surroundings. I go by the genetics theories. In my case I have gone back 9 generations on both parents side and was not able to find stuttering, but that doesn’t mean one might have been a stutterer. I also remember learning that stuttering can jump a generation or multiple generations. On my father’s side there is well documented that Parkinson’s are in the family. High chance that my father will be diagnosed with Parkinson, my two brothers and myself. So weird with the human body.