Yes definitely has a genetic component to it. My dad stutters, his brothers, and his mom. Researchers have also identified the stuttering gene. They found it in song birds well (From a Huberman podcast). So it doesn't just exist in humans. Some people are the first and only ones in the family though but it's rare. Side note: 4 times as many boys stutter than girls, which means brain differences between boys and girls make boys more susceptible.