(a) A decree of adoption, whether issued by a court of this state or by a court of any other jurisdiction, shall have the following effect as to matters within the jurisdiction of or before a court in this state:

(1) Except with respect to a spouse of the petitioner and relatives of the spouse, a decree of adoption terminates all legal relationships between the adopted individual and his relatives, including his parent, so that the adopted individual thereafter is a stranger to his former relatives for all purposes, including inheritance and the interpretation or construction of documents, statutes, and instruments, whether executed before or after the adoption is decreed, which do not expressly include the individual by name or by some designation not based on a parent and child or blood relationship; and

(2) A decree of adoption creates the relationship of parent and child between each petitioner and the adopted individual, as if the adopted individual were a child of biological issue of that petitioner. The adopted individual shall enjoy every right and privilege of a biological child of that petitioner; shall be deemed a biological child of that petitioner, to inherit under the laws of descent and distribution in the absence of a will, and to take under the provisions of any instrument of testamentary gift, bequest, devise, or legacy, whether executed before or after the adoption is decreed, unless expressly excluded therefrom; shall take by inheritance from relatives of that petitioner; and shall also take as a "child" of that petitioner under a class gift made by the will of a third person.

(b) Notwithstanding the provisions of subsection (a) of this Code section, if a parent of a child dies without the relationship of parent and child having been previously terminated by court order or unrevoked surrender of parental rights to the child, the child's right of inheritance from or through the deceased parent shall not be affected by the adoption.