Burnets Forbidden Clone Theory postulates that unlucky somatic gene mutations in multiplying lymphocytes produce the Forbidden Clones that cause the autoimmune diseases.Graves disease is caused by Forbidden Clones of B lymphocytes, whereas forbidden clones of T lymphocytes cause Type 1 Diabetes.The H Gene Theory of Adams and Knight postulates that Histocompatibility antigens, major, minor and H-Y, dictate the immune repertoire by deleting nascent complementary clones, altering the risk of occurrence of the autoimmune diseases.