Colorado Revised Statutes Title 19. Children's Code § 19-4-110. Parties

The child may be made a party to the action. If the child is a minor, the court may appoint a guardian ad litem. The child's mother or father may not represent the child as guardian or otherwise. The court shall make the natural mother, each man presumed to be the father under section 19-4-105, and each man alleged to be the natural father parties or, if not subject to the jurisdiction of the court, provide notice of the action in a manner prescribed by the court and an opportunity to be heard. If a man who is alleged to be the natural father is deceased, the court shall make the personal representative of his estate, if one has been appointed, a party. If a personal representative has not been appointed, the court shall make the deceased man's spouse or an immediate blood relative a party. If a spouse or immediate blood relative is not known or does not exist, the court shall appoint a representative for the alleged natural father who is deceased. The court may align the parties. When the person to be served has no residence within Colorado and his or her place of residence is not known or when he or she cannot be found within the state after due diligence, service must be by publication pursuant to rule 4(g) of the Colorado rules of civil procedure;  except that service must be by a single publication and must be completed not less than five days prior to the time set for hearing on paternity adjudication.