A circuit court may, as part of a proceeding for the adoption of a child born in a foreign country or upon petition to amend a certificate of birth for a person born in a foreign country, correct or establish a date of birth for such person. In cases in which adoptive parents are unable to ascertain the date of birth of the child or in which medical evidence indicates that the stated date of birth of the child is incorrect, the court may establish a corrected date of birth based on medical evidence of the child’s actual age and the State Registrar of Vital Records shall issue a certificate of birth pursuant to § 32.1-261 showing the date of birth established by the court.