I have known of several babies with diabetes.  One was a 9-month old who
was in the hospital when my daughter was in after her initial diagnosis.  In
the diabetes parents' group I attended, there were a couple of families whose
kids had been diagnosed as babies.
     Professionally, I have worked with a woman whose 18-month old was
diagnosed with diabetes.  His breastfeeding seemed to be a plus in that it
prevented low blood sugar.  Although it may have made it more difficult to
maintain good control, this is not considered realistic in toddlers anyway.
 We all know how erratic their eating is and how difficult it would be to get
a toddler to eat certain amounts of certain things at certain times only.  In
young children, low blood sugar is more dangerous than high blood sugar,
since it can cause brain damage, so breastfeeding would be an advantage.
     As for the 23-year old, if he/she has had those symptoms for almost a
year, it is not likely to be diabetes.  She would have gotten seriously ill
long before this.  But I can't imagine a doctor refusing to test.  All it
takes is dipping a test strip in some urine.

                   Miriam Levitt RN, IBCLC