People assume a stutter is from trauma (head injury) or anxiety (public speaking), but there's also a huge genetic link which seriously isn't well investigated. Not really sure if you can do this, but maybe talk to gebeicists and speech language pathologists about the genetic component of stuttering? I rarely ever hear people talk about stuttering as a child and having it run in their family (both me and my dad stutter) so it'd be nice shining light on that topic.