In the comments on the previous post re Customary Adoption, the isue arose about inheritance rights between natural family members subsequent to termination of parental rights and adoption. So, here it is per Child Welfare Information Gateway:
* Alaska, Idaho, Illinois, and Maine provide for a continuation of inheritance rights if stated in the adoption decree.
(IF STATED - how many mothers losing their rights know what?)
* In Kansas, Louisiana, Rhode Island, Texas, and Wyoming, an adoption decree terminates the right of the birth parent to inherit from the adopted person, but the adopted person may still inherit from the birth parent.
* In Colorado, if there are no other heirs, the adopted child may file a claim against the estate of the birth parent within 90 days of the parent's death.
* Illinois allows the birth parents to acquire from the adopted child's estate any property gained from them through gift, will, or under intestate laws.
* In Pennsylvania, an adopted person may inherit from the estate of a birth relative, other than a birth parent, who has maintained a family relationship with the adopted person.
Of course, subsequent to reunion, or knowing the identity of a child you've lost to adoption, they can be included in your will IN ANY STATE.