Our daughter, age 20 months, was diagnosed with Type 1 diabetes at age 15 months. What is the chance of having another child with Type 1 Diabetes? Neither my husband nor I or anyone in our families has Type 1 diabetes. I did not have gestational diabetes while pregnant, nor have any other women in my family. One doctor told us we had a 10% chance. Another doctor told us 3%. One endocrinologist said in their practice of 250 patients, they have about 20 who are diabetic siblings (8%). My daughter's pediatrician said they don't have any patients who have diabetic siblings; they have about 80 diabetic patients.
The overall risk of a second child developing Type 1 Diabetes is somewhere around 1:30; but it varies geographically and in relation to the particular HLA genetic markers that you and your husband carry. At this time there is no sure way of calculating the probability more precisely in your specific family circumstances.
There are several studies in progress in both North America and Europe to find out if diabetes can be predicted in early infancy and if some form of 'vaccination' might be effective and also to detect diabetes before it is clinically apparent and to see if insulin dependence can be prevented or averted.