What are the odds of someone with type 1 diabetes passing it on to their child?

Depends. If you are a father with type 1 diabetes on average 7% of your children will develop type 1. For mothers the odds are ~3%. Overall about 4% of first degree relatives of someone with type1 will develop type 1 diabetes in their lifetimes.
Type 1 diabetes is . An autoimmune disorder that has no specific inheritance pattern. Sometimes whole families can suffer from it but in other cases, only one person might have it. Another fact is that more often than naught if you have type 1 someone else in your family will as well. It is also thought that type 1 diabetes owes it's creation to a person't environment.Please read more.