Proceedings for the adoption of a minor child and for a change of name of such child shall be instituted only by petition to a circuit court in the county or city in which the petitioner resides, in the county or city in which the child-placing agency that placed the child is located, or in the county or city in which a birth parent executed a consent pursuant to § 63.2-1233. Such petition may be filed by any natural person who resides in the Commonwealth, or who has custody of a child placed by a child-placing agency of the Commonwealth, or by an adopting parent of a child who was subject to a consent proceeding held pursuant to § 63.2-1233, or by intended parents who are parties to a surrogacy contract. The petition shall ask leave to adopt a minor child not legally the petitioner’s by birth and, if it is so desired by the petitioner, also to change the name of such child. In the case of married persons, or persons who were previously married who are permitted to adopt a child under § 63.2-1201.1, the petition shall be the joint petition of the husband and wife or former spouses but, in the event the child to be adopted is legally the child by birth or adoption of one of the petitioners, such petitioner shall unite in the petition for the purpose of indicating consent to the prayer thereof only. If any procedural provision of this chapter applies to only one of the adoptive parents, then the court may waive the application of the procedural provision for the spouse of the adoptive parent to whom the provision applies. The petition shall contain a full disclosure of the circumstances under which the child came to live, and is living, in the home of the petitioner. Each petition for adoption shall be signed by the petitioner as well as by counsel of record, if any. In any case in which the petition seeks the entry of an adoption order without referral for investigation, the petition shall be under oath. A single petition for adoption under the provisions of this section shall be sufficient for the concurrent adoption by the same petitioners of two or more children who have the same birth parent or parents, and nothing in this section shall be construed as having heretofore required a separate petition for each of such children. The petition for adoption, except those filed pursuant to subdivisions 4 and 5 of § 63.2-1210, shall include an additional $50 filing fee that shall be used to fund the Virginia Birth Father Registry established in Article 7 (§ 63.2-1249 et seq.) of this chapter. A petition filed while the child is under 18 years of age shall not become invalid because the child reaches 18 years of age prior to the entry of a final order of adoption. Any final order of adoption entered pursuant to § 63.2-1213 after a child reaches 18 years of age, where the petition was filed prior to the child turning 18 years of age, shall have the same effect as if the child was under 18 years of age at the time the order was entered by the circuit court provided the court has obtained the consent of the adoptee.