Not necessarily
Only some small studies say it CAN come from a transmitted virus or some shyt, but thats nothing concrete.
Im a type 1 diabetic so i know. I got it from my fathers side apparently (have no relatitonship but i heard years after) even tho i strangely got it
before him. I got it as a 7 y/o. Im not obese, i didnt even alot of sugar, i ran around & played like every other kid..
Type 1 is 99% genetic. This is why usually get it either as a child, teen or young adult.