No one knows exactly how type 1 diabetes is passed on, but many believe that it is likely inherited, and most people with type 1 diabetes get it before the age of 30. Environmental factors may play a role, and viruses and toxins that damage the pancreas have also been explored, but no one knows the exact cause of how type 1 diabetes is passed on.
In type 2 diabetes, either the pancreas does not make enough insulin or the body does not use it properly. No one knows the exact cause of how type 2 diabetes is passed on, but there are some key diabetes risk factors that can trigger type 2 diabetes, such as being overweight, having a family history of diabetes, and certain pregnancy conditions.