34 C.F.R. §300.20.  Parent.

(a) General. As used in this part, the term parent means--

(1) A natural or adoptive parent of a child;

(2) A guardian but not the State if the child is a ward of the State;

(3) A person acting in the place of a parent (such as a grandparent or stepparent with whom the child lives, or a person who is legally responsible for the child's welfare); or

(4) A surrogate parent who has been appointed in accordance with Sec. 300.515.

(b) Foster parent. Unless State law prohibits a foster parent from acting as a parent, a State may allow a foster parent to act as a parent under Part B of the Act if--

(1) The natural parents' authority to make educational decisions on the child's behalf has been extinguished under State law; and

(2) The foster parent--

(i) Has an ongoing, long-term parental relationship with the child;
(ii) Is willing to make the educational decisions required of parents under the Act; and
(iii) Has no interest that would conflict with the interests of the child.