When can natural parents of an adopted child regain contact with their adopted child?

As stated by Weatherston, J., in Lyttle v. Children’s Aid Society of Metropolitan Toronto, supra, at p. 137: On the other hand, the sense of security of the child in his new home ought not to be disturbed readily. He must continue to know that this is indeed his home; that he is entitled to demand the loyalty of his new parents and that he is obliged to give them his loyalty in return. That sense of security and loyalty would be diminished if the adopting parents felt that a natural parent could interfere with the affection of the child, or their authority over him. They might feel that they were mere custodians of the child, with less than ordinary parental rights and responsibilities. Another factor, of general public policy, which I think is almost conclusive with children’s aid societies, is that prospective adopting parents would be more difficult to find if they were generally aware that natural parents might be permitted to regain contact with adopted children.