In most cases, who is (are) the usual and appropriate surrogate decision maker(s) for a newborn?

The parents are the usual and appropriate surrogate decision makers for a newborn. The child was the product of their love so they should be the one to decide for the child. It could be inferred that they would be deciding for the betterment of the child because it is assumed that the parents love the child. Therefore, parents are the appropriate surrogate decision maker for a newborn except if proven otherwise.