I wasn't there for their childhoods so it's hard to judge, especially when some situations can be worse on paper but better in reality and vice versa, and there are ones who probably had rough childhoods but rarely talk about it (seems to be the default in MMA to have a hard childhood), but Jens, Huerta, War Machine, Ngannou's all sound pretty sad or scary. At the same time, most of them had an outlet in MMA or another combat sport so it wasn't all bad, compared to those without any outlet (Ngannou didn't have an outlet, he had to go and make one as an adult by going to France).