If you do decide to have a child (there’s no real predicting the risk of your kid having T1), you will recognize the symptoms. Obsessively testing will do nothing other than set up probably emotional/mental issues in the child.
There are no guarantees in life. Would I not want the life I’ve led? I’ve so far had a terrific life, in great part due to excellent parents. I have T1 and nothing’s stopped me. You shouldn’t act as though developing T1 would cause your child to lead an unpleasant life. And having parents who know and understand T1? Even better. So decide to have a child or not. Decide whether or not you can be great parents. Those are the most important issues. T1 is not a tragedy.