The risk of developing schizophrenia in first degree relatives of schizophrenic patients is elevated compared to the risk of the general population (0.9%). Parents of schizophrenic patients have a lifetime prevalence of 11%, and siblings have a prevalence of 9%. Identical twins have a 50% chance of suffering from schizophrenia if their sibling has it. Children of schizophrenics have a lifetime prevalence of 12.8%. Reference: Kaplon and sadock, 11 th edition, synopsis of psychiatry, 11 th edition, pg no. 310