750 ILCS 46/303: Denial of parentage.

A presumed parent may sign a denial of parentage. The denial is valid only if:

(a) a voluntary acknowledgment described in Section 301 of this Act signed, or otherwise authenticated, by a person is filed pursuant to Section 305 of this Act;

(b) the denial is in a record, and is signed, or otherwise authenticated, under penalty of perjury; and

(c) the presumed parent has not previously:

(1) acknowledged parentage, unless the previous voluntary acknowledgment has been rescinded under Section 307 of this Act or successfully challenged under Section 308 of this Act; or

(2) been adjudicated to be the parent of the child.