How to Get a Court-Ordered DNA Test in Illinois

If you need to confirm or dispute who a child's genetic parent is, Illinois law allows you to ask the court to order DNA testing as part of a parentage case. Subject to limited exceptions, a judge can require the child, the person who gave birth, and the person whose parentage is being determined to participate in testing.^[1]

The results can become important evidence in deciding legal parentage. Once parentage is established, the court may also address child support, parenting time, and the allocation of parental responsibilities.

Before filing, it helps to understand who may request testing, how the process works, what the results mean, and what can happen if someone refuses to cooperate.

When You Can Ask the Court to Order a DNA Test

Any party to a parentage case or the child may request genetic testing. A court or administrative hearing officer may also direct testing as part of the proceeding. Subject to limited exceptions, the court must order testing when a party or the child properly requests it.^[1]

Illinois Department of Healthcare and Family Services Child Support Services may also arrange testing when it is helping establish parentage or child support. HFS states that genetic testing is free for the custodial parent and child through its administrative process, although an alleged genetic parent may be required to pay for testing.[10]

There are limits. Genetic testing cannot be used to challenge the parentage of someone who is a parent under Illinois assisted-reproduction or gestational-surrogacy laws. It also cannot be used to establish a sperm or egg donor as the child's legal parent.^[8]

How the Testing Process Works, Step by Step

1. File or Respond to a Parentage Case

A judicial parentage case begins with a petition to adjudicate parentage.

The parentage proceeding may generally be filed in any Illinois county where one of the parties resides. A proceeding seeking the allocation of parental responsibilities is commenced in the county where the child resides.^[2]

2. Request Genetic Testing

Once the case is open, a party or the child may ask the court to order DNA testing. The request may be included in the petition, raised through a motion, or made during the court proceedings.^[1]

HFS may also arrange testing through its administrative Child Support Services process when the family is receiving those services.^[10]

3. The Court Appoints a Qualified Expert

Court-ordered genetic testing must be conducted by an expert qualified to examine blood or tissue types and appointed by the court.

The testing must use a method reasonably relied upon by professionals in the genetic-testing field. It must also be performed by a laboratory accredited by the American Association of Blood Banks, now known as AABB, or a successor organization.^[3]

4. DNA Samples Are Collected

Samples are commonly collected by rubbing a swab inside each person’s cheek. The process is generally quick and does not require a blood draw.

Although cheek swabs are common, Illinois law permits specimens consisting of blood, buccal cells, bone, hair, other body tissue, or bodily fluid. The appointed expert determines the appropriate testing procedure.^[3]

5. The Expert Reports the Results

The testing expert prepares a written report. If the person being tested is not excluded as a possible genetic parent, the report must include a combined parentage index and a statistical probability of parentage.^[4]

The expert may be called to testify about the testing and the results. Illinois law also provides procedures for documenting the chain of custody and admitting a properly verified report into evidence.^[4]

Are At-Home DNA Tests Accepted in Illinois Court?

An at-home or consumer DNA test is not automatically accepted as evidence in an Illinois parentage case.

Illinois law allows a party to obtain certain genetic testing independently of the testing ordered by the court and to present expert testimony interpreting the results. Reports of independent testing and information about the experts who will interpret them generally must be provided to the other parties at least 30 days before the parentage hearing.^[9]

An unsupervised drugstore or mail-in test may have evidentiary problems because the court may not be able to verify:

• Who provided each sample
• Whether the samples were altered or contaminated
• How the samples were handled
• Whether the laboratory was properly accredited
• Whether the report was properly authenticated
• Whether a reliable chain of custody was maintained

For these reasons, a court-ordered test or a properly conducted independent test is generally more useful in a parentage case than a private consumer kit.

What a 99.9% Result Means

Illinois law creates a rebuttable presumption of parentage when genetic testing:

• Does not exclude the alleged genetic parent
• Produces a combined parentage index of at least 1,000 to 1
• Shows a probability of parentage of at least 99.9%^[5]

A rebuttable presumption means the court starts with the legal assumption that the tested person is the child’s parent, unless qualifying evidence overcomes that assumption.

The result is strong evidence, but it is not the final parentage judgment by itself. The court or administrative agency must still enter a legal determination of parentage.

The person identified by the test may challenge the presumption with additional genetic testing that either excludes that person as a genetic parent or identifies someone else as a possible genetic parent. If testing identifies more than one possible genetic parent, the court must order further testing to determine parentage.^[5]

What Happens If Someone Refuses to Test

Refusing a court-ordered DNA test does not resolve the case in the refusing party's favor. Illinois law gives the court discretion to adjudicate parentage contrary to the position of a party who declines testing, and a testing order can be enforced through contempt proceedings if a party disregards it.^[5]

Neither outcome is automatic. The court weighs the circumstances of the refusal before deciding how to proceed, but a party who declines testing should not assume that refusing makes the paternity question go away.

If the parent refusing is specifically the child's mother, our page on when a mother refuses DNA testing walks through why this shows up and how the case still moves forward.

Who Pays for the Test

Illinois law does not assign every genetic-testing expense to the same person.

The party who requests testing is generally responsible for the expense. However, the court may divide the cost between the parties when asked to do so.^[7]

If the person requesting testing to establish parentage is found indigent, the public agency providing representation may be responsible for the cost. If no public agency is providing representation, the county where the case was filed may be responsible.^[7]

The county is also responsible when the court orders testing on its own motion or when an indigent alleged or presumed parent requests the testing. The court may later treat some testing expenses as court costs, subject to the limits in the statute.^[7]

HFS may arrange genetic testing through its Child Support Services process. HFS states that testing is free for the custodial parent and child in its administrative process, although the alleged genetic parent may be required to pay.^[10]

When a Court May Deny a DNA Test Request

A court does not automatically order genetic testing in every case.

When a child already has a presumed, acknowledged, or adjudicated parent, the court may deny testing only if it finds all three of the following:

1. The prior conduct of the relevant parent legally prevents that person from denying parentage.
2. Disproving the existing parent-child relationship would be inequitable or unfair.
3. Denying testing would be in the child’s best interests.^[1] [8]

The first requirement is sometimes described by saying the person is estopped from denying parentage.

In plain language, estopped means legally prevented from taking a position because the person’s previous conduct would make that position unfair. For example, the court may consider whether someone acted as the child’s parent for a significant period and whether disrupting that established relationship could harm the child.

When deciding whether the requirements are met, the court considers factors such as:

• How long the person acted as the child’s parent
• When the person learned they might not be the genetic parent
• The circumstances surrounding that discovery
• The relationship between the person and the child
• The child’s age
• The potential harm to the child
• The relationship between the child and another alleged parent
• Whether the passage of time has made it harder to establish another person’s parentage
• Other facts affecting fairness and the child’s best interests[8]

When the child requests testing, Illinois law presumes that granting the request is equitable and in the child’s best interests. That presumption may be overcome only by clear and convincing evidence that extraordinary circumstances would make testing contrary to the child’s best interests.^[1]

If You Want a Second Opinion on the Results

If the results do not exclude the alleged father, either party can ask the court for an independent retest by a different qualified expert before the case moves forward. This gives both sides a way to confirm accuracy before paternity is finalized.

If you already went through testing, or paternity was established without it, and you believe the outcome is wrong, Illinois's process for challenging an existing paternity finding lays out the strict deadlines and legal standard involved in reopening that determination.

How This Fits Into Establishing Paternity in Illinois

Court-ordered DNA testing is one piece of a larger case. Illinois recognizes voluntary acknowledgment, an administrative order through HFS, and a judicial order as three separate paths to legal fatherhood, and you can review all three on our Illinois paternity overview.

If paternity hasn't been established at all yet, our full breakdown of how paternity gets established in Illinois covers the Voluntary Acknowledgement process, what happens if you want to walk it back after signing, and how the administrative and judicial routes differ.

How Sterling Lawyers Can Help

Sterling Lawyers handles paternity and parentage cases across Illinois for a fixed fee, so you know the total cost of your legal representation before the case begins.

Whether you are requesting genetic testing or responding to a testing request, our team can explain the filing process, help you prepare for testing, and address what the results may mean for child support, parenting time, and the allocation of parental responsibilities.

See Your Path Forward

Book a consultation to discuss your next steps, from filing the petition through the court's final parentage determination.