Can Established Paternity Be Challenged in Illinois?

 Posted on September 04, 2026 in Paternity

Learning that you may not be a child's biological father can raise difficult questions, especially when paternity has already been legally established. You may be wondering whether it is too late to question a legal relationship that is already in place.

In Illinois, established paternity can sometimes be challenged, but there are rules and deadlines for doing so. If you have questions about paternity in 2026, an Arlington Heights, IL paternity attorney can review your case and explain your options.

Can I Take Back a Voluntary Acknowledgment of Paternity in Illinois?

A person who signed a Voluntary Acknowledgment of Paternity may have a short window to take it back. Illinois law now refers to this document as a voluntary acknowledgment of parentage.

Under 750 ILCS 46/307 of the Illinois Parentage Act, a signer can rescind an acknowledgment before whichever comes first: sixty days after the acknowledgment takes effect, or the date of a court or administrative proceeding about the child in which the signer is a party, including a child support proceeding.

Keep in mind that the signer may lose the right to take back the acknowledgment once a child support case involving parentage begins. Once the rescission period has passed, the signer must meet stricter requirements to challenge it.

How Can I Challenge an Acknowledgment in Illinois After the Deadline to Take It Back?

After the rescission period ends, an acknowledgment can only be challenged for specific legal reasons. According to 750 ILCS 46/309, those reasons are fraud, duress, or a material mistake of fact.

The challenge generally must be filed within two years after the acknowledgment took effect. However, certain periods involving legal disability or duress are not counted toward that two-year deadline.

The person bringing the challenge must prove the claim by clear and convincing evidence. It’s important to know that this is a higher level of proof than the standard used in many civil cases.

Can a Presumed Parent Challenge Paternity in Illinois?

A presumed parent is someone whom Illinois law already treats as a child's parent based on certain circumstances, such as marriage to the person who gave birth. A presumed parent may be able to challenge paternity. However, they must bring the challenge within two years after learning, or when they should have learned, the facts behind the challenge.

There are exceptions to this rule. For example, the law allows certain cases to be filed at any time if the presumed parent and the person who gave birth did not live together or have sexual relations during the probable time of conception.

Will a DNA Test Automatically Change Established Paternity in Illinois?

A DNA test alone does not automatically change legal parentage in Illinois. A court may still need to decide whether an existing parent-child relationship should be changed.

Under 750 ILCS 46/610, the court can consider the child's existing relationship with the parent. The judge may look at how long the person has acted as a parent and when the person learned they might not be the biological parent. The court can also consider the harm that changing the relationship could cause the child.

Illinois law also allows a court to deny a request for DNA testing in some cases involving an established parent-child relationship. For this reason, a private DNA result should not be treated as proof that a person's legal obligations to the child have ended.

Do I Still Have to Pay Child Support While Challenging Paternity?

A pending challenge usually does not stop a person's legal duties as a parent. This includes an existing duty to pay child support. For a challenge to a voluntary acknowledgment, Illinois law states that the court generally cannot suspend the signer's legal responsibilities while the case is pending unless there is good cause.

A person should not stop paying court-ordered child support simply because a paternity challenge has been filed. An attorney can explain whether the court may change an existing order based on the circumstances of the case.

Contact an Arlington Heights, IL Paternity Lawyer

If you have questions about established paternity or believe an existing parentage decision should be challenged, the attorneys at Cosley Law Office can help. Attorney Donald J. Cosley personally handles every part of your case. When you call with questions about your case, you will speak with him, your legal representative, and will not be passed off to a paralegal.

Contact a Rolling Meadows, IL paternity attorney for a free consultation or call 847-253-3100 today.