How to Establish Paternity in the United States

Reviewed by DocDraft Legal Team · United States · Last updated September 12, 2026

Establishing paternity means legally identifying a child's father or second parent so the child gains rights to support, custody and visitation, health coverage, inheritance, and benefits. In every state there are two main paths. Unmarried parents who agree can sign a Voluntary Acknowledgment of Paternity, sometimes called a Voluntary Declaration of Parentage, usually at the hospital after birth or later at the state child-support agency. This process is federally mandated for every state that receives federal child-support funding (42 U.S.C. 666(a)(5); 45 CFR 303.5), and one rule is uniform nationwide: after signing, either parent generally has 60 days to rescind the acknowledgment. Once that window closes, a signed acknowledgment carries the force of a court judgment and can be challenged only on narrow grounds such as fraud, duress, or material mistake of fact, and even a later genetic test may not be enough to undo it. When parents do not agree, or a child is born during a marriage, a court decides parentage, often after ordering genetic testing. Almost everything else varies by state: the statute of limitations to bring a court paternity action, the marital presumption of paternity and how it is rebutted, the genetic-testing probability threshold, the agency that handles cases, and the exact acknowledgment form. Attorney review of your situation is available through DocDraft.