(750 ILCS 46/621)
    Sec. 621. Binding effect of determination of parentage.
    (a) Except as otherwise provided in subsection (b) of this Section, a determination of parentage is binding on:
        (1) all signatories to an acknowledgment or denial as
    
provided in Article 3 of this Act; and
        (2) all parties to an adjudication by a court acting
    
under circumstances that satisfy the jurisdictional requirements of Section 201 of the Uniform Interstate Family Support Act.
    (b) A child is not bound by a determination of parentage under this Act unless:
        (1) the determination was based on an unrescinded
    
acknowledgment as provided in Article 3 of this Act and the acknowledgment is consistent with the results of genetic testing;
        (2) the adjudication of parentage was based on a
    
finding consistent with the results of genetic testing and the consistency is declared in the determination or is otherwise shown;
        (3) the child was a party or was represented in the
    
proceeding determining parentage by a guardian ad litem, child's representative or attorney for the child; and
        (4) the child was no longer a minor at the time the
    
proceeding was initiated and was the moving party resulting in the parentage determination.
    (c) In a proceeding for dissolution of marriage, civil union, or substantially similar legal relationship, declaration of invalidity of marriage, civil union, or substantially similar legal relationship, or legal separation, the court is deemed to have made an adjudication of the parentage of a child if the court acts under circumstances that satisfy the jurisdictional requirements of Section 201 of the Uniform Interstate Family Support Act, and the final order:
        (1) expressly identifies a child as a "child of the
    
marriage, civil union, or substantially similar legal relationship", "issue of the marriage, civil union, or substantially similar legal relationship", or uses similar words indicating that a party to the marriage, civil union, or substantially similar legal relationship is the parent of the child; or
        (2) provides for support of the child by the parties
    
to the marriage, civil union, or substantially similar legal relationship, unless parentage is specifically disclaimed in the order.
    (d) Except as otherwise provided in subsection (b) of this Section, a determination of parentage may be a defense in a subsequent proceeding seeking to adjudicate parentage by an individual who was not a party to the earlier proceeding.
    (e) A party to an adjudication of parentage may challenge the adjudication only under the laws of this State relating to appeal, vacation of judgments, or other judicial review.
(Source: P.A. 99-85, eff. 1-1-16.)