My dad had a severe stutter growing up, and he still stutters. His father stuttered, too, though it was milder. A couple of my brothers stuttered as very young children, but grew out of it. Now that I have a son it's something that's been on my mind and that's why I've hopped onto this subreddit. There's no clear "stuttering gene" like there is for other inherited conditions (my eye condition for instance), but it seems there's definitely some genetic component in many cases. At the same time, my dad is an identical twin and his twin never had a stutter, so go figure.... All everyone can agree on is that stuttering is very complicated and that there are a whole mix of different factors at work.