I've never heard about parents passing it down. It definitely isn't true in my case, but we only have records to great grandparents and there is zero stuttering in my family. I had alot of ear infections as a kid and always thought this was it? I also have a cousin with a tic disorder and suspect it's linked somehow. Could you consult a genetic counselor in India? It's pretty standard in the US to have genetic counseling, especially if you're over a certain age.