I always say, when I get a grey hair out of nowhere, it was coz of one of my kids. But I actually think grey hair is genetic, and not related to stress. But I have NO scientific evidence to back this up. Just saying though, with 3 grown up kids, including one with a drug addiction, 2 divorces, IVF and moving countries, then states, I should probably have a full head of grey hair if it was stress-related!