Type 2 definitely has a genetic component to it. I know it runs in my wifes family, they basically all have it, wife got diabetic at second pregnancy, had to take insulin, it has now regressed but she is stil teetering on the edge, not even that overweight either.
Thats why I tell my kids all the time to watch what they eat, not all food is good for you. My older son is 14 and like 6ft, 135, but eats nothing but junk all day. The fucker will eat dry pasta if there is no snack shit around. He could pound out a whole box of cereal in less than a day.
The younger son is who I worry about though. He is going to be 12 now, but is 5'8" or 9" but 175. Quite chubby and loves to eat like a boss.