Whenever, in any action involving the custody or support of a child apparently born in lawful wedlock, the parentage of the child is placed in issue, the court may make the child a party to the action, if not already a party, and shall thereupon determine the parentage of the child as one of the issues in the action. The court shall appoint a guardian ad litem to represent the interests of the child and may assess the reasonable fees and expenses of the guardian ad litem as costs of the action, payable in whole or in part by any or all parties as the circumstances may justify. In the event the child is not made a party to the action, a determination that the child was not born to parents married to each other at the time of the child’s birth shall not be binding upon the child.