Never. Although I know people who don’t want to have children because of the (pretty small) risk of them getting diabetes. While I wouldn’t wish diabetes on anyone, it really isn’t that awful that I’d rather my parents had aborted me than make me “suffer” the life I have.
Of course, if you were an evil state trying to reduce healthcare costs, removing Type 1’s from the system before they even enter it would save a nice chunk of money.