I would literally have a simple conversation that goes as follows: 1. Dad I noticed you repeated words that I struggled with. 2. I assume you know that I have a speech condition called a stutter, which is often a hereditary condition inherited from the father 3. I also assume you do not suffer from stuttering 4. When I heard you repeat what was a struggle for me, I felt it was mocking me 5. Did you intend to make fun of my medical condition? And then be quiet. Walk away if there is no response. Don’t say “it’s okay” because it’s not. And do NOT let it eat you up. Some theories: 1. As a parent they are genuinely unhappy about it and it’s a way of poorly processing 2. They are genuinely mocking and that’s bad Either way it’s bad