Anyone who has adopted a child, or been adopted, probably knows this, but for everyone else, remember this: When it comes to inheritance, you only have one father or one mother. While sometimes we distinguish between a “biological mother” and an “adoptive mother,” when it comes to being an “heir,” there can be only one mother. That would be your natural (biological) mother UNLESS another woman (including a grandmother or a stepmother) legally adopts you.
Adoption is not the same as raising a child, or having custody. Adoption is going to court and getting a judgment or decree of adoption, legally cutting the ties with one parent and giving it to a new parent.
So, if Luke is legally adopted by a stepfather, when it comes to being a legal heir only that stepfather can say, “Luke, I am your father.” Luke will inherit nothing from his biological father. The opposite is true also. If Luke grows up and dies without a spouse or descendant, his heirs are his parents, which means his mother and his adoptive father.
Of course, if the natural father dies before the adoption, then Luke can inherit from both. You can have two fathers under the law, just not two fathers at the same time.
And if Luke’s biological father leaves a Will giving a share to Luke, that would work. So you can leave a child, whom you gave up for adoption, part of your estate, but only through a Will.
Must the parents be married in order for the child to inherit? In Florida, no. “Illegitimate children” (those born out of wedlock) have the same inheritance rights as children born of legally married parents.