Hi Martin,
I know of 3 T1 fathers who have children who have developed T1, but wouldn't have known this unless i'd went to a Diabetic kids weekend. My own son is T1 and the only other member in my family is my Mums sister, so therefore my Aunt. In my opinion, todays world, enviroment has as much to play with diabetes as genetics does. A lot of conditions are on the increase, asthma, autism, even hayfever, and all of these are as much genetic as they are enviromental. Gives you more to think about, but i wouldn't let it stop you from having children. Having a child with diabetes isn't the easiest thing in the world, but neither is it the hardest,
Take care,
Suzi x