(a) Any person eighteen years of age or older may, by written agreement with another person at least eighteen years of age but younger than himself or herself, unless the other person is his or her spouse, brother, sister, uncle or aunt of the whole or half blood, adopt the other person as his or her child, provided the written agreement shall be approved by the Probate Court for the district in which the proposed adoptive parent resides or, if the proposed adoptive parent does not reside in this state, for the district in which the adopted person resides.

(b) The Probate Court shall cause notice of the time and place of hearing on the proposed adoption to be given to each party to the adoption agreement. If the spouse of the proposed adoptive parent is not a party to the adoption agreement, notice shall be given to the spouse. The court may give notice to other persons interested in the welfare of the proposed adoptive parent or adopted person. The court shall approve the adoption agreement if it finds that the proposed adoptive parent and adopted person share a relationship that is similar to that between a parent and an adult child and that the adoption is in the best interests of the proposed adoptive parent and adopted person. Upon the court’s approval of the adoption agreement, the adopted person shall become the legal child of the adoptive parent, and the adoptive parent shall become the legal parent of the adopted person, and the provisions of § 45a-731 shall apply.

(c) One parent of an adult child may join in an adoption agreement between the parent’s spouse and the adult child. Upon the court’s approval of the adoption agreement, the legal relationship between the adult child and the parent who did not join in the adoption agreement shall be terminated in accordance with subdivisions (5), (6) and (7) of § 45a-731, and the adopted person shall be the child of the parent and spouse who joined in the adoption agreement, except that the adoption shall not affect the rights of the adopted person to inherit from or through a parent who died before the adoption occurred, as provided in subdivision (8) of § 45a-731.

(d) One parent of an adult child may join in an adoption agreement between one other person and the adult child. Upon the court’s approval of the adoption agreement, the legal relationship between the adult child and the parent who did not join the adoption agreement shall be terminated in accordance with subdivisions (5), (6) and (7) of § 45a-731, and the adopted person shall be the child of the parent and other person who joined the adoption agreement, except that the adoption shall not affect the rights of the adopted person to inherit from or through a parent who died before the adoption occurred, as provided in subdivision (8) of § 45a-731.

(e) A married person shall not adopt a person under the provisions of this section unless both the married person and the married person’s spouse join in the adoption agreement, except that the Probate Court may approve an adoption agreement by either of them upon finding that there is sufficient reason why the other should not join in the agreement.