Section 8. On complaint to establish paternity, the court shall make a judgment establishing or not establishing paternity which shall be determinative for all purposes. Upon default of the defendant or his failure to personally appear, the court shall make a judgment establishing paternity if a showing is made that the complaint was served in accordance with the applicable rules of court and that the mother or putative father submits that sexual intercourse between the parties occurred during the probable period of conception. For good cause shown, the court may set aside an entry of default and, if a judgment has been entered, may likewise set it aside in accordance with rule 60(b) of the Massachusetts Rules of Domestic Relations Procedure. The age of the person alleged to be the father or mother in any action under this chapter, including a filing of a voluntary acknowledgment of parentage, shall not be a bar to the establishment of paternity or entry of a support order pursuant to section nine. If the child or the mother on behalf of the child is a recipient of public assistance and if the department of transitional assistance, the department of social services, the division of medical assistance or any other public assistance program has not been made a party as required by section five, the court shall notify the IV-D agency as set forth in chapter 119A of the judgment. If the judgment is at variance with the child’s birth certificate, the court shall order that a new birth certificate be issued under section thirteen of chapter forty-six.