PHOENIX – The Arizona Supreme Court today ruled that a biological father can go to court to prove he is a child’s father, even if another man has already signed a legal document claiming that role. The decision in Strang v. Malay/Hernandez settles conflicting lower-court rulings on how Arizona’s paternity laws fit together.
Under Arizona law, unmarried parents can sign an “acknowledgment of paternity,” a voluntary document that carries the force of a court judgment and can be challenged only within a short window and on narrow grounds. Alternatively, a man who says he is the biological father can ask a court to establish paternity in a separate lawsuit.
The question in this case was whether the deadlines that govern challenges to acknowledgments also bar a biological father—one who never signed the acknowledgment—from later bringing his own lawsuit.
In this case, a child was born to Caitlin Malay in September 2021. Christian Hernandez signed an acknowledgment of paternity, which the state accepted in October 2021. Both Hernandez and Malay believed he was the biological father. Genetic testing in November 2023 pointed to Tyler Strang as the biological father, and a second test in June 2024 confirmed that result.
Strang went to court in 2024 to establish his paternity, but the superior court dismissed his claim, ruling that the earlier acknowledgment and its deadlines barred his lawsuit. Strang asked the Supreme Court to review that decision.
Writing for the majority, Justice Maria Elena Cruz held that a biological father who never signed an acknowledgment is not barred from bringing his own lawsuit. Once he establishes a competing legal presumption that he is the father, the superior court must weigh the two presumptions and decide which one controls.
The Court explained that Arizona’s paternity laws form a single framework and must be read together. A signed acknowledgment is just one of several ways to establish a presumption of paternity—not a final decree that automatically defeats every other claim. The deadlines and finality rules, the Court reasoned, bind the people who signed the acknowledgment. They do not erase the separate right to a lawsuit the Legislature created for a father who never signed an acknowledgment.
The Court added that reading the statutes this way avoids a serious constitutional concern: a biological father’s protected interest in building a relationship with his child.
The Court stressed that its ruling is narrow. It does not set aside Hernandez’s acknowledgment, does not decide who the child’s legal father is, and does not decide which presumption ultimately controls. Those questions—along with any defenses and consideration of the child’s welfare—remain for the superior court to resolve.
The Court vacated the dismissal and returned the case to the superior court for further proceedings.
Vice Chief Justice Lopez and Justices Beene and King dissented.
