1. I regret to say that once you were legally adopted, your acquire rights to the estates of your adopted parents. However, you loose your rights to any share in your natural father's estate, or to your natural mother's estate. I regret to say that there is no way in which this can be undone. Once you were adopted you lost your previous rights to a share in your natural father's estate. You could probably seek to challenge the constitutionality of this legal rule. However, as things stand, you will not get a share in your natural father's estate, I regret to say. Additionally, any constitutional challenge is unlikely to succeed.