(a) Subject to the limitations hereinafter set forth, consent to or relinquishment for adoption of a minor child is required of:

(1) The parents or surviving parent of a marital child, whether adult or infant;

(2) The outsider father of a marital child who has been adjudicated to be the father of the child or who has filed a paternity action which is pending at the time of the filing of the petition for adoption;

(3) The birth mother of a nonmarital child, whether adult or infant; and

(4) The determined father.

(b) Consent or relinquishment shall not be required of a parent or of any other person having custody of the adoptive child:

(1) Whose parental rights have been terminated pursuant to the provisions of §49-4-114 of this code;

(2) Whom the court finds has abandoned the child as set forth in §48-22-306 of this code; or

(3) Who, in a stepparent adoption, is the birth parent or adoptive parent of the child and is married to the petitioning adoptive parent. In such stepparent adoption, the parent must assent to the adoption by joining as a party to the petition for adoption.

(c) If the mother, legal father, or determined father is under disability, the court may order the adoption if it finds:

(1) The parental rights of the person are terminated, abandoned, or permanently relinquished;

(2) The person is incurably insane; or

(3) The disability arises solely because of age and an otherwise valid consent or relinquishment has been given.

(d) If all persons entitled to parental rights of the child sought to be adopted are deceased or have been deprived of the custody of the child by law, then consent or relinquishment is required of the legal guardian or of any other person having legal custody of the child at the time. If there is no legal guardian nor any person who has legal custody of the child, then consent or relinquishment is required from some discreet and suitable person appointed by the court to act as the next friend of the child in the adoption proceedings.

(e) If one of the persons entitled to parental rights of the child sought to be adopted is deceased, only the consent or relinquishment of the surviving person entitled to parental rights is required.

(f) If the child to be adopted is 12 years of age or over, the consent of the child is required to be given in the presence of a judge of a court of competent jurisdiction, unless for extraordinary cause, the requirement of such consent is waived by the court.

(g) Any consent to adoption or relinquishment of parental rights shall have the effect of authorizing the prospective adoptive parents or the agency to consent to medical treatment for the child, whether or not such authorization is expressly stated in the consent or relinquishment.