How is paternity established?
Acknowledgment of Paternity. A form both parents sign, commonly at the hospital after birth. Once signed and filed it has the force of a court order.
For a signatory aged 18 or older, Family Court Act §516-a generally permits rescission by petition within 60 days of signing or before the response date in a related proceeding, whichever comes first. Special timing applies to a signatory under 18. Later challenges require proof of fraud, duress or material mistake of fact, and child-protective limits can still prevent testing.
This matters because people sign the form at an emotional moment, sometimes without certainty, and treat it as provisional. It is not.
Paternity petition. Either parent, or in some circumstances the child or a public agency, can file in Family Court. The court can order genetic testing, and on the results makes an order of filiation declaring legal parentage.
Marriage. A child born to married parents is presumed to be the child of the marriage. That presumption is strong and is not overcome simply by asserting otherwise.
Genetic testing is not automatic
This surprises people who assume a test settles everything.
New York courts can decline to order genetic testing where doing so would not serve the child’s best interests — most commonly where a man has held himself out as the father, the child has a settled relationship with him, and disturbing that relationship would harm the child. The doctrine is equitable estoppel, and it can bar testing regardless of what the biology would show.
It cuts both ways. It can prevent a biological father from establishing parentage where another man has filled the role, and it can prevent a man who raised a child from disclaiming support after years of acting as the father.
Under Family Court Act §516-a and Shondel J. v Mark D., equitable estoppel protects the child’s interests in an established parental relationship. Biological proof alone does not decide whether testing should be ordered; the court considers the child’s best interests on the facts.
Why timing matters more here than almost anywhere
Delay changes the legal position, not just the practical one. A relationship that becomes established while a case sits unaddressed can become the basis for estoppel later. If parentage is genuinely in question, raise it early rather than waiting to see how things develop.
What follows an order of filiation
Once paternity is established, the ordinary framework applies — custody and parenting time, child support, and the ability to seek modifications later.
Frequently asked questions
How is paternity established in New York?
By a signed and filed Acknowledgment of Paternity, or by an order of filiation from Family Court under Article 5 of the Family Court Act. A child born to married parents is presumed to be the child of the marriage.
Can I undo an Acknowledgment of Paternity?
For adult signatories, the usual rescission deadline is the earlier of 60 days after signing or the response date in a related proceeding. Different timing applies to signatories under 18. Later challenges require proof of fraud, duress or material mistake of fact; equitable estoppel and other child-protective rules can limit testing.
Will the court always order a DNA test?
No. A court can decline to order genetic testing where it would not be in the child’s best interests — typically where a settled parent-child relationship already exists.
Do I have to establish paternity to get custody or visitation?
Yes. An unmarried father has no enforceable custody or visitation rights until legal parentage is established.
Does establishing paternity mean I owe child support?
It creates the obligation. Support is then calculated under the Child Support Standards Act.
Related: Child Custody & Parenting Time · Child Support · back to Family Law
Written by Dale Riedel, Esq. · Admitted in New York, Bar No. 5837539 · Last reviewed October 6, 2026