I bow down to your insurmountable knowledge @alison – I was told a long time ago my odds would be 50% by my childhood DSN 
Nice to know the numbers might not be that bad!
Can you do the maths for a T1 father (diagnosed at 2) and a non diabetic mother with a T1 father (diagnosed at 35?) 
(I will add in my defence that I’m not the only one on the world wide inter web cloud who has been told the 50% figure for a T1 father.)
Ah yes, I had forgotten about the “cull” ….. 