On September 14, 2026, the Arizona Supreme Court ruled 4 to 3 in Strang v. Malay/Hernandez that a biological father can ask a court to establish his paternity even after another man has signed an Arizona acknowledgment of paternity for the same child.
Appellate courts had been giving trial judges conflicting answers on whether a signed acknowledgment, which carries the force of a court judgment, closes that door for good. For a man who never signed it, the Court said no, though a right to a hearing isn’t the same as a win.
Key Takeaways of the Court’s Ruling
- A biological father who never signed an acknowledgment of paternity can file his own paternity case, and the acknowledgment’s deadlines don’t automatically block him.
- Once he proves a competing presumption, such as genetic testing showing at least a 95% probability of paternity, the judge weighs it against the acknowledgment.
- Nobody has won yet, because the Court sent the case back to Maricopa County Superior Court without setting aside the acknowledgment.
- A man who signed remains bound by the 60-day window to rescind, or cancel, the acknowledgment.
The Facts Behind the Strang Paternity Case
- A child was born to Caitlin Malay in September 2021.
- Malay and Christian Hernandez signed an acknowledgment of paternity, and the state accepted it in October 2021.
- DNA tests in April 2022 ruled out Hernandez as the child’s biological father.
- DNA tests in November 2023 and June 2024 confirmed Tyler Strang as the biological father.
- Strang petitioned for paternity in late 2024.
- The Superior Court dismissed Strang’s petition based on the Malay and Hernandez’s signed acknowledgment.
- The Supreme Court reversed and vacated the dismissal.
What Did the Arizona Supreme Court Decide in Strang v. Malay/Hernandez?
The Court decided that a biological father who wasn’t a party to an acknowledgment of paternity can still bring his own paternity case. Justice Maria Elena Cruz wrote the majority opinion, joined by Chief Justice Timmer and Justices Bolick and Montgomery. Vice Chief Justice Lopez and Justices Beene and King dissented.
Three Arizona laws drive the decision:
- Arizona Revised Statutes Section 25-812 lets unmarried parents sign an acknowledgment that carries the force of a court judgment.
- Section 25-803 lets a father, among others, start a court case to establish paternity.
- Section 25-814 lists the ways a man can be presumed the father and tells judges how to choose when two presumptions collide.
The opinion sides with the 2017 Court of Appeals decision in Brummond v. Lucio and disapproves parts of four other appellate rulings that treated an acknowledgment as the last word.
Why the Arizona Supreme Court Said a Signed Acknowledgment Doesn’t Close the Door
The Court reasoned that an acknowledgment of paternity binds the people who signed it and nobody else.
A Signed Acknowledgment Is One Presumption Among Several
Arizona’s paternity laws list a signed acknowledgment beside genetic testing as ways to presume a man is the father. If an acknowledgment always worked as a final decree, the Court explained, that listing would do nothing, because it could never be weighed against another presumption.
This means the judge compares them and picks the one supported by what the statute calls “weightier considerations of policy and logic.”
A Constitutional Concern Shaped the Reading
The Court also pointed to a biological father’s protected interest in building a relationship with his child, recognized in the 1983 U.S. Supreme Court decision Lehr v. Robertson. Erasing that interest without notice or a hearing would raise a serious constitutional question, so the Court chose the reading that avoids it.
What the Dissenting Justices Said
Vice Chief Justice Lopez, joined by Justices Beene and King, argued that the majority’s reading puts finality and stability for children at risk. The dissent made three main points:
- A filed acknowledgment establishes legal paternity with the force of a court judgment, so it should be challenged only through the narrow route the statutes provide.
- A man could come forward years later, even when the child is 17, and reopen who the legal father is.
- Strang, the dissent noted, suspected he might be the father before the child was born, so the constitutional concern fit his case poorly.
The majority replied that the acknowledgment stays effective during the new case and that a father’s knowledge and delay can still be raised as defenses.
What Strang Leaves Undecided, and Why Timing Will Matter
The Court did not set aside Hernandez’s acknowledgment, did not decide who the child’s legal father is, and did not say which presumption wins. Those questions went back to Maricopa County Superior Court, where the opinion leaves delay, reliance, and the child’s welfare open for the judge to weigh.
What the Strang Ruling Means for Fathers, Mothers, and Signers
The ruling affects biological fathers, men who signed acknowledgments, and mothers in different ways.
If You’re a Biological Father
You can ask a court to establish your paternity without meeting the narrow grounds that apply to signers. Genetic testing showing at least a 95% probability gives you a presumption, and the judge then weighs it against the acknowledgment.
The ruling gets you a hearing, not a result.
If You Signed an Acknowledgment
Your acknowledgment stays in force, and undoing it still takes either a rescission within the 60-day rescission window, using the Arizona Department of Economic Security’s rescission affidavit, or a later challenge based on fraud, duress, or material A later challenge must be filed within the short time limit in Arizona Family Law Rule 85(c), so talk to an attorney.
What changes is that a biological father can now ask the court to weigh his presumption against yours, so keep records of the care, support, and time you’ve given the child.
If You’re the Child’s Mother
An acknowledgment no longer guarantees that a biological father can’t come forward later. If there’s doubt about who the biological father is, genetic testing before anyone signs can settle the question before it returns as a custody case, and if a case is already underway, expect to be a central witness.
A conversation with an Arizona paternity attorney at Ellsworth Family Law, P.C. early, before filings and deadlines stack up, gives you room to choose a strategy instead of reacting to one.
Ellsworth Family Law’s Experience With Paternity and Appeals
Ellsworth Family Law, P.C. has practiced family law exclusively since opening in Mesa in 2003, and an Arizona paternity attorney at the firm handles paternity cases and family law appeals.
- Founding partner Steven M. Ellsworth has practiced in Arizona since 1989, is a State Bar of Arizona certified family law specialist. He is a Fellow of the American Academy of Matrimonial Lawyers who served as its Arizona chapter president in 2021 and 2022. Super Lawyers named him to its list in 2008 and in each year from 2010 through 2026.
- Partner Glenn D. Halterman, also a certified family law specialist, was counsel of record for the appellant in two Arizona Court of Appeals opinions, Mitton v. Mitton in 2017 and Walker v. Walker in 2023.
- F. Taylor Larson, admitted in Arizona in 2016, was named a Super Lawyers Rising Star in 2026.
Frequently Asked Questions
How long does a biological father have to file for paternity in Arizona?
Arizona law sets no general deadline for filing a paternity case, only an 18th-birthday cutoff for seeking child support. The Supreme Court confirmed in Strang that a case can start during the pregnancy or any time after the birth. Even so, waiting hands the other side a delay argument, so you’ll want to file as soon as your testing is in hand.
Can a man cancel an acknowledgment of paternity after he signs it?
Yes, either parent can rescind within the earlier of 60 days after the last signature or the date of a court proceeding about the child, such as a child support case. After that window closes, the only route is a court challenge based on fraud, duress, or material mistake of fact, so talk to an attorney before the 60 days run out.
What happens to child support if a man who signed an acknowledgment isn’t the biological father?
If his challenge succeeds and clear and convincing genetic evidence shows he isn’t the biological father, the court vacates, or cancels, the paternity determination and ends his ongoing support, but only going forward. That order doesn’t erase back support, and the Court in Strang left the fate of Hernandez’s support obligations to the trial judge. Keep paying until a judge says otherwise, because state law doesn’t suspend support during a challenge unless the court finds good cause.
Can a biological father get parenting time before paternity is established?
Not until a court establishes paternity, but you can ask for legal decision-making and parenting time in the same case. State law lets the judge decide them together, and the parent the child has lived with for most of the last six months holds legal decision-making unless the court orders otherwise.
Ellsworth Family Law, P.C.: Your Paternity and Family Law Firm
Whether a DNA result changed what you thought you knew or your name sits on an acknowledgment you signed years ago, paternity questions carry significant weight. At Ellsworth Family Law, P.C. in Mesa, our attorneys guide clients through every step of paternity and family law proceedings. Contact our firm today to schedule a consultation.
