robert2003
It appears that once you are 21 years of age, you can set aside the adoption and have your birth certificate restored. The following information is from the Idaho General Statutes:
TITLE 16
JUVENILE PROCEEDINGS
CHAPTER 15
ADOPTION OF CHILDREN
16-1509A. DISSOLUTION OF ADOPTION. An adoption may be dissolved, upon
petition, with the agreement of both the adoptee and the adopting parent, when
the adopting parent was the spouse of a natural parent, and the marriage of
the natural parent and adoptive parent was terminated. If the petition for
dissolution occurs after the death of the adoptive parent, the court shall, in
the finding of dissolution, specify the effect upon rights of inheritance. The
court must determine that avoidance of statutory care is not the purpose of
the dissolution, unless the court finds grounds to waive this finding. An
action to obtain a decree of dissolution of adoption may be commenced at any
time after the adoptee reaches twenty-one (21) years of age.