Genetics isn't necessarily the reason people outgrow their stutter. You seem to be thinking of stuttering as this fixed thing and if the cause is genetic, then you cant do anything. That's oversimplifying the condition of stuttering. What you can do is work on your stuttering. IMO mostly through eliminating avoidance behaviors, cleaning up how you speak so you're only showing clean up stuttering which doesnt interfere that much with communication. In order to do most of that, you really need to accept your stutter and accepting showing it. When you block, you're holding back on stuttering. If you were ok and accepted your stuttering instead of trying to hold it back, you would just stutter the sound out and move on, instead of blocking. that's what you do.