

Genetic disposition for the body to produce antibodies that attack and kill insulin producing beta cells. There are 2 types, GAD and TSH antibodies. They are normally present at birth, but sometimes get triggered later in life by a cold/flu. There are a few mysteries in the exact mechanics, but I agree, overall, it is pretty well understood.
Imagine your the foremost expert in the world on tortoise mating and your settling into the theatre for the new hit movie, Jurassic Park.