The commonest reason for gall bladder stones in children is chronic haemolytic disease or spherocytosis. Cystic fibrosis is another disease in which children may get gall stones or with chronic liver disease. Sick premature babies have also been found to have gall stones especially after parenteral nutrition in the neonatal period. I would recommend that you should see a Paediatric Gastroenterologist, who can guide you further.