When Can Paternity Be Challenged in Texas?

 Posted on April 22, 2026 in Family Law

Paternity questions do not always come with simple answers. Sometimes a man is listed as a child's father on a birth certificate when the child's biological father is someone else entirely. Other times, a man signs documents without fully understanding what they mean or what he is giving up. 

In Texas, the law offers ways to challenge a paternity determination if you act in time, but the rules are specific, and the deadlines are strict. If you have questions about your situation, a San Antonio, TX family law attorney who handles paternity matters can help you understand your options before it is too late.

How Does Texas Law Define a Presumed Father?

Under Texas Family Code Chapter 160, a man is legally presumed to be a child's father in several situations. He is presumed to be the father if he was married to the child's mother at the time of the child's birth. The same is true if the child was born before the 301st day after the marriage ended. If a couple married after the child was born and the husband was named on the birth certificate or agreed to support the child, paternity is also presumed. Finally, if a man lived in the same home as the child from birth through the child's first two years and acted as the father, the law presumes he is the legal father.

These presumptions exist to protect children and give them a stable legal identity. However, they can create problems when the presumed father is not the biological father. The law provides a path to challenge them, but only under certain conditions and within certain time limits.

How Paternity Is Established in Texas and What an Acknowledgment Means

When parents are not married, a man can voluntarily become the legal father by signing an Acknowledgment of Paternity (AOP). This is a legal document that carries real weight. Signing an AOP establishes a parent-child relationship with all the rights and duties that accompany it, including child support obligations and custody rights.

Parents should not sign an AOP unless they are certain about the biological connection. If there is any doubt, genetic testing should be done first. DNA testing is widely available and can confirm or rule out a biological relationship before anyone signs legal documents. Once signed, undoing an AOP becomes much harder.

When Can a Paternity Acknowledgment Be Canceled in Texas?

There is a short window to back out of a signed AOP. A person has 60 days from the date the acknowledgment was filed to submit a rescission, which is a formal cancellation. This process must follow the specific steps set out in the Texas Family Code. If the 60-day window passes, the options narrow significantly.

After the rescission period closes, a challenge to the AOP can only succeed if one of these applies:

• Fraud: Someone actively deceived the man into signing, such as by falsely claiming he was the biological father.

• Duress: The man was threatened or pressured into signing against his will.

• Material mistake of fact: Both parties genuinely but incorrectly believed the man was the biological father.

The person challenging the AOP carries the burden of proof. Simply having doubts is not enough. You need evidence that one of these three conditions actually existed when the document was signed.

Texas Deadlines for Challenging a Presumed Father's Paternity

When no AOP is signed, and a man is simply presumed to be the father, the challenge must be filed before the child's fourth birthday in most cases. Missing that deadline does not always end the matter, but it raises the bar considerably.

Texas law does allow a challenge after the four-year mark if two specific conditions are met. First, the presumed father and the mother were not living together and were not in a sexual relationship around the time the child was conceived. Second, the presumed father missed the deadline only because he genuinely believed he was the biological father. Courts examine these claims carefully. Acting quickly when doubts first arise is always the better approach.

What DNA Testing Can and Cannot Do in a Texas Paternity Case

Genetic testing is often the centerpiece of a paternity challenge. Under Texas Family Code Section 160.631, a court can order genetic testing as part of a parentage proceeding. If testing shows a man is not the biological father, the court will usually rule that he is not the legal father, unless other legal barriers apply.

However, DNA results alone do not automatically resolve the case. Courts still weigh the legal relationship that already exists, deadlines that have passed, and whether the child's best interests should factor into the outcome. In some cases, a man who is not the biological father may still be treated as the legal father if he waited too long to act or if the circumstances do not meet one of the legal grounds for challenge.

This is why having a clear legal strategy matters as much as the test results themselves.

What Happens to Child Support and Custody if Paternity Is Successfully Challenged in Texas?

If a court determines that a man is not the legal father, his future child support obligation usually ends, but any unpaid past support may still be owed. He also loses any parental rights he may have had, including the right to custody or visitation. This is a significant trade-off that deserves careful thought before pursuing a challenge.

On the other side, if a man wants to establish paternity rather than challenge it, doing so through a court order or a valid AOP gives him enforceable rights to be involved in his child's life. A man who suspects he may be a child's biological father but has never been legally recognized has no custody or visitation rights until legal paternity is established.

Frequently Asked Questions About Paternity Challenges in Texas

Can a mother challenge paternity in Texas? 

Mothers have standing to petition the court to challenge a paternity determination, including an AOP signed by someone who is not the biological father. The same grounds and deadlines apply.

What if the biological father is unknown? 

Texas courts can still adjudicate parentage even when the biological father has not been identified. In some cases, the court may order testing of potential fathers if there is enough information to proceed.

Does a paternity challenge affect the child's last name? 

A successful paternity challenge removes the legal father-child relationship, but changing a child's name requires a separate legal process.

Can a man be forced to take a DNA test in Texas? 

Courts do have this authority. Under Texas Family Code Section 160.502, a court can order genetic testing for any man named in a parentage proceeding.

Talk to a Bexar County, TX Family Law Attorney About Your Paternity Case

Paternity disputes involve tight deadlines and real legal consequences. Whether you are trying to establish legal fatherhood or challenge a paternity determination that may not reflect the truth, you need an attorney who focuses on these issues. At Brandon Wong & Associates, we practice family law exclusively, which means our attorneys bring deep, focused knowledge to every case we handle. Contact our San Antonio, TX family law lawyer at 210-201-3832 to schedule a consultation.