34 CFR 303.27 - Parent.
(a)Parent means -
(3) A guardian generally authorized to act as the child's parent, or authorized to make early intervention, educational, health or developmental decisions for the child (but not the State if the child is a ward of the State);
(4) An individual acting in the place of a biological or adoptive parent (including a grandparent, stepparent, or other relative) with whom the child lives, or an individual who is legally responsible for the child's welfare; or
(1) Except as provided in paragraph (b)(2) of this section, the biological or adoptive parent, when attempting to act as the parent under this part and when more than one party is qualified under paragraph (a) of this section to act as a parent, must be presumed to be the parent for purposes of this section unless the biological or adoptive parent does not have legal authority to make educational or early intervention service decisions for the child.
(2) If a judicial decree or order identifies a specific person or persons under paragraphs (a)(1) through (a)(4) of this section to act as the “parent” of a child or to make educational or early intervention service decisions on behalf of a child, then the person or persons must be determined to be the “parent” for purposes of part C of the Act, except that if an EIS provider or a public agency provides any services to a child or any family member of that child, that EIS provider or public agency may not act as the parent for that child.