You are well aware that in India caste based reservation is there in educational and employment facilities. A person who belongs to these castes can avail himself these facilities till these reservations exist in our system. You being not in any reserved category (I am not using the word forward caste), but your husband belongs to OBC, your child as per the prevailing law declared by the Supreme Court, acquires the caste of his father, i.e., OBC. He will be eligible to avail OBC reservation facilities in future. If you both take a bold decision of not mentioning caste in respect of your child, he may deprive the reservation facility in future. That is what some of the advisers are suggesting that it may create future complications for the child. If your child also will become as much bold and as much progressive as both of you and respect your decision, then go ahead and not mention the caste of the child.