Sometime in the early to mid 90's there was a study being done to prevent diabetes in children who might carry a genetic factor that caused diabetes.  My daughter had been part of that study because I myself am a type 1 diabetic and have been since I was 9 moths old, even though there were no other known cases of diabetes in my family.  If the child did in fact carry what they thought was a genetic factor for diabetes they were entered into the study.  

The study consisted of three groups.  The group was then divided into two separate groups once determination was made if the child did carry the supposed genetic marker and a control group.  

In the first group, those children received a small dose of insulin every day for several months to two years.   After a period of time the insulin was stopped and they watched to see if the children later developed diabetes.  In the second group, the children were given nothing, but were followed to see if they ever developed diabetes.  The control group was considered to be a normal group of children selected randomly who did not have what they thought was the genetic factor period.  In the control group, they would be followed to see if they remained diabetes free, or if they still were to develop diabetes.  

Although I had asked to know the results of the tests, there was no way of knowing if my daughter had genetic maker or not.  She was followed for several year I assume as part of the control.  The only way a parent would know if they did have the marker was if they were in the first group mentioned and were given that dose of daily insulin.  

I don't know what the study showed in the end as we were never told and I never heard anything else about it.  But I would think that the researchers of the study my daughter was in, must have known far ahead of the study mentioned here that this was already possible to do.  Otherwise why attempt it?