Yes! BUT I don't think I stutter more for the same reasons as you. My brother and I stuttered almost as equally when we were kids. But his almost grew away. We bot had the repetitions stutter but nowadays a merely have the "freezing-stutter" and not that bad. But yes I stutter so much more around my brother but I think it's because I'm so comfortable around him that I don't care how I speak. I would say I'm a 7/10 stutterer around my brother. I've noticed the same with my parents and now my gf of 2 years and some of my best friends. The more comfortable I am with the person the more I stutter. Maybe a 4-6/10 with these people. I would say that I'm a 2-4/10 stutterer in public depending on the day.