(a) In determining the best interest of the child, the court may not deny or delay the adoption or otherwise discriminate on the basis of race or ethnicity of the child or the prospective adoptive parents.
(b) This section does not apply to a person, entity, tribe, organization, or child custody proceeding subject to the Indian Child Welfare Act of 1978 (25 U.S.C. § 1901 et seq.). In this subsection “child custody proceeding” has the meaning provided by 25 U.S.C. § 1903.