Wis. Stat. § 48.92
A valid adoption of the petitioner by his aunt would preclude his right to inherit as the son of his natural mother, although he would be entitled to inherit as a nephew. Estate of Komarr, 68 Wis. 2d 473, 228 N.W.2d 681 (1975). Biological grandparents had no right to visitation following termination of their son's parental rights and adoption by the child's stepfather. In re Marriage of Soergel, 154 Wis. 2d 564, 453 N.W.2d 624 (1990). The adoption of a child of a deceased parent does not terminate the decedent's parents' grandparental visitation rights under s. 880.155 [now s. 48.9795(12)]. H.F. v. T.F., 168 Wis. 2d 62, 483 N.W.2d 803 (1992). Except in the case of stepparent adoption, the parental rights of both birth parents are terminated, effectively preventing a birth parent's nonmarital partner from adopting the birth parent's child. This provision does not violate the constitutional rights of either the child or nonmarital partner. Interest of Angel Lace M., 184 Wis. 2d 492, 516 N.W.2d 678 (1994). Adoption proceedings confer all parental rights on the adoptive parents and therefore resolve all issues relating to the biological grandparents' rights to assert claims for custody and guardianship. Following adoption, a change requires a showing of unfitness in the adoptive parents. Elgin and Carol W. v. DHFS, 221 Wis. 2d 36, 584 N.W.2d 195 (Ct. App. 1998), 97-3595. Sub. (2) does not nullify prior support arrearage obligations for which a natural parent became liable before that parent's parental rights were terminated. Hernandez v. Allen, 2005 WI App 247, 288 Wis. 2d 111, 707 N.W.2d 557, 04-2696.