This depends on whether your spouse/partner has type
1 or type 2 diabetes. In the case of type 1 diabetes, in general the risk of type 1 diabetes is 10 times as great in a first-degree relative compared to the risk in the population at large. A first-degree relative is your par- ent, sibling, or child. The general population risk of type 1 diabetes is about one-third to one-half of 1%, i.e., about 1 in 200 to 250 people. In a first-degree relative of someone with type 1 diabetes, this increases to about 1 in 20 to 25 people or about a 4% or 5% chance. Most people consider that this is not a suffi- ciently high risk to deter them from having a family, but that is of course a personal and individual decision. The likelihood of developing type 1 diabetes declines with age, about 90% of cases being diagnosed younger than age 35.
In the case of type 2 diabetes, the risk is considerably higher and a general rule is that if both parents have type 2 diabetes, about two out of three of their chil- dren will develop it. If one parent has type 2 diabetes, about one out of three of their children will be affected. Decision making using these rough estimates is difficult. Most people destined to develop type 2 diabetes will not do so in their child-bearing years. Therefore, it is not really possible to estimate risk to the future children when it is as yet unknown whether the parents will get diabetes. Although type 2 diabetes is a highly inherited disorder, the risk of developing it can be very powerfully changed by an individual’s lifestyle. Even people with a high hereditary risk may not get type 2 diabetes if they maintain a healthy weight and exercise regularly. However, if your spouse/partner has type 2 diabetes, you can factor in your own parents’ health history in the risk to your future children. If either of your parents has type 2 diabetes, this increases the risk to your child to more than one in three. Of course, in contrast to type 1 dia- betes, type 2 diabetes tends to develop later in life, so children at risk are still most likely to have a healthy childhood and diabetes-free youth.