The cause of Type 1 Diabetes is unknown. This is a well known scientific fact, especially among us T1's.
People of lesser intellectual prowess will always assume that Type 1 Diabetes is caused by an overindulgence of candy and ice cream at a young age. Please try hard not to punch these folks if they approach you with their theories.
I'm sure you've thought about it...so what's your theory? What causes our immune system to go haywire? Why are there more and more Type 1's popping up everywhere? Is it an alien virus?...the environment?...a government conspiracy?
What do you think?