In normal circumstances, as per Supreme Court ruling and as per administrative circulars issued by various State Govts. the child acquires the caste of the father. The exception is that if he shows that he lived and brought up in the surroundings of his mother, he can claim the caste of his mother. But in your case no problem arises as the children are foregoing their economic and social benefits available under S.C., they can claim the caste of O.C. without having any hinderance. The problem arises onlly when the father belongs to O.C. and mother belongs to S.C. or S.T. and the children seek the economic and social concessions available to her mother's caste. My reply is on the basis of the Supreme Court judgements, which I cannot recall for your ready reference.