How to Establish Paternity When Parents Aren't Married

When a married woman gives birth, the law in every state generally presumes her husband is the child’s other legal parent. When an unmarried woman gives birth, the law doesn’t presume anything. Someone has to take an affirmative step—called “establishing paternity”—to make the father a legal parent.

State laws and procedures on how to establish paternity vary, so check your own state’s rules before you sign a voluntary acknowledgment of paternity (VAP) or get an order establishing paternity through a child support agency or court.

What Does “Establishing Paternity” Mean?

Establishing paternity means naming a child’s legal father. Once that happens, the father is a legal parent, with all the rights and responsibilities that come with that relationship.

To understand the process of establishing paternity, it helps to understand three terms:

• Biological father. The man who actually fathered the child, though having a biological connection with a child doesn’t automatically make him a legal parent.
• Alleged or putative father. A man who might be the father, or who claims to be, but whose paternity hasn’t been settled yet.
• Legal father. The man the law recognizes as the child’s parent. Only a legal father can ask for custody or parenting time, and be ordered to pay child support.

Some states now use the word “parentage” instead of “paternity” and use gender-neutral forms. The federal child support program still uses “paternity” in its rules. Regardless of what terminology is used, the process is the same.

Who May Establish Paternity?

Legal fathers have a duty to financially support their children at least until they turn 18 or become emancipated. So a child’s mother, or another relative with custody of the child, may file a paternity petition as a first step toward seeking child support from the father.

If the mother or legal custodian is receiving public assistance on the child’s behalf, or has applied for child support services through a state child support agency, the agency may file a paternity petition.

And, finally, the alleged father may also seek to establish paternity to be recognized as the father.

Why Does Establishing Paternity Matter?

Establishing paternity matters for an alleged father in two ways: he needs it before he can seek custody or parenting time, and it helps guard against losing his rights if the child is later placed for adoption. 

For mothers or legal custodians, establishing paternity is a prerequisite to getting a court-ordered child support award. 

But it's the child who often benefits the most. Beyond a connection with the father and his family, establishing paternity can open the door to:

• child support
• health insurance benefits
• government benefits (like Social Security and veterans), and
• inheritance rights.

Three Ways to Establish Paternity

Unmarried parents can establish paternity in three ways: by signing an acknowledgement, by going through a state child support agency, or by getting a court order.

Voluntary Acknowledgment of Paternity (VAP)

The most common way unmarried parents establish paternity is by voluntarily signing a form. Depending on where you live, the form might be called an “acknowledgment of paternity,” “affidavit of parentage,” or “voluntary declaration of parentage.”

Federal law requires that every state have these forms available at hospitals and birthing centers. If both parents sign the form soon after birth, no DNA test is required, and the father’s name goes on the birth certificate. If the parents don’t sign the form at the hospital, they can sign it later at a vital records office, a child support agency, or before a notary, depending on the state.

A properly signed acknowledgment of paternity is a legal finding of paternity, with the same effect as a court order.

(42 U.S.C. § 666 (2026).)

Request Services From Your Local Child Support Agency

Federal law requires every state to run a child support agency. In addition to establishing and enforcing child support orders, these agencies establish paternity.

Usually, the mother or legal custodian asks the agency to help establish paternity, but an alleged father who wants to establish (or contest) paternity can also apply. Or the agency itself may start the process if the child is receiving public assistance.

The agency will order DNA tests for the alleged father, the mother, and the child. If the tests show that the alleged father is the biological father, he and the mother may then sign and submit a VAP. Otherwise, the agency will file a petition to establish paternity in court.

(42 U.S.C. § 654; 45 C.F.R. § 303.5 (2026).)

File a Petition to Establish Paternity in Court

If you’re the alleged father, the mother, or the child (often through a guardian), you may file a petition directly with the court to establish paternity. The judge may then order DNA testing to prove that the alleged father is (or isn’t) the biological father.

Depending on the test results, the parties either consent to an order establishing paternity or have a contested hearing and let the judge decide if paternity has been established or ruled out.

If paternity is established, the judge will often set child support in the same order and direct the vital records office to add the father’s name to the child’s birth certificate.

How DNA Testing Works in Paternity Cases

Modern DNA testing is minimally invasive and extremely reliable. It usually requires only a cheek swab from the mother, the child, and the alleged father.

You can purchase at-home kits, but courts and child support agencies won’t accept these results. To be legally admissible, a sample must be taken by a neutral collector who checks photo IDs, seals the samples, and documents the “chain of custody” from collection to lab.

When the child support agency handles the case, the agency typically pays for the test up front, but can bill the father after the results establish paternity.

(45 C.F.R. § 303.5 (2026).)

Paternity Isn’t the Same as Custody

Legal parents have a duty to financially support their children. So, paternity is linked to child support. But an order establishing paternity doesn’t necessarily entitle a father to custody or parenting time.

Instead, in most states, a father seeking custody usually has to file a separate request, and a judge will decide what custody arrangement is in the best interests of the child.

Can You Cancel a Voluntary Acknowledgment of Paternity?

If you have any doubt about paternity, it’s best to get a DNA test before you sign anything. A VAP is hard to undo.

Federal law gives either parent a short window to rescind (cancel) a VAP for any reason, with no explanation required. The window typically closes at 60 days. A few states allow more time. Procedures for how to rescind an acknowledgement vary by state. Some use a form filed with the vital records department; others may involve a local child support agency or court. 

Rescinding is a one-sided move. You don't need the other parent's agreement to cancel an acknowledgment. However, rescission only cancels the paperwork. It doesn't settle the issue of paternity. If the mother or the child support agency still thinks you're the father, they can pursue establishing paternity through the other channels outlined above, which likely means a DNA test. 

If you're thinking of trying to walk back an acknowledgment of paternity, check your state’s rules and talk to a family law attorney or a staff member at the court’s self-help center right away.

Once the window to rescind closes, an acknowledgment is treated as a legal finding of paternity. You can only challenge it in court, usually by proving fraud, duress, or a material mistake of fact. Even then, some states bar a challenge in court after a certain amount of time, often two to four years.

(42 U.S.C. § 666 (2026).)

Can You Disestablish Paternity?

Many states have a specific process for a man to challenge paternity if he learns he isn’t the biological father of the child. These laws usually require the man to act soon after he learns the truth. When paternity is disestablished, child support ends. However, it typically doesn’t require the father to be reimbursed for past support paid.

Some courts publish statewide forms to disestablish paternity and terminate child support (example: Florida).

Do I Need a Lawyer to Establish or Dispute Paternity?

Most unmarried couples don’t need a lawyer to establish paternity. If both parents agree on who the father is, they can simply sign a VAP at the hospital, and you don’t need a lawyer to open a case with a child support agency either.

But if you have any doubt about who fathered the child, it's worth talking to a family law attorney—ideally, before you sign anything. The same goes if you're trying to undo an acknowledgment of paternity you already signed, or if you’ve been named as the father of a child and don’t believe you are.

If you can’t afford a lawyer, free help is often available through family court self-help centers and legal aid offices.