The state Supreme Court made it harder for same-sex couples to be listed on the birth certificates of their children.

The Arkansas Supreme Court today struck down a lower court’s ruling that would have allowed married same-sex couples to have both spouses listed as parents on their children’s birth certificates without obtaining a court order.

Justice Josephine Linker Hart, writing for the court’s majority, cited what she called “basic biological truths” in overturning Pulaski County Circuit Judge Tim Fox’s 2015 ruling, the Associated Press reports.

“In the situation involving the female spouse of a biological mother, the female spouse does not have the same biological nexus to the child that the biological mother or the biological father has,” Hart wrote. “It does not violate equal protection to acknowledge basic biological truths.”

Cheryl Maples, the attorney for three same-sex couples in the case, said that sets a different standard than the one applied to straight couples. “There’s no requirement that DNA be given or that there be a biological relationship to a child to get on a birth certificate for a father, for the non-birth parent,” she told the AP. “All you have to do is legitimize the child and you’re entitled, if you’re heterosexual. This is wrong.”

Maples said she hasn’t decided whether to appeal the ruling to the U.S. Supreme Court, the AP reports.

In November 2015, Fox ruled that because the state recognizes same-sex marriages, the couples were automatically entitled to have both their names listed on their children’s birth certificates. The Arkansas Health Department’s Vital Statistics Bureau had told them they would have to get a court order to be listed, although there is generally no such requirement for opposite-sex couples.

Fox initially applied his ruling only to the three couples who brought the case, but he said he would issue an order broadening it to apply to all same-sex couples in Arkansas. However, a few days after the decision, the Arkansas Supreme Court put it on hold, saying it could lead to confusion and uncertainty. The couples in the suit were all allowed to obtain birth certificates with both parents’ names. Not having both names on the birth certificate can lead to problems with matters such as taking out health insurance or even being allowed to pick up a child at school.

In her ruling today, Hart admonished Fox for “inappropriate remarks” in his decision. “The gist of Judge Fox’s remarks was that if this court granted the stay, then it would deprive persons of their constitutional rights, and that this court previously had deprived people of their constitutional rights in a separate matter,” she wrote. His statement, she said, violated the state’s code of judicial conduct because it could undermine public confidence in the judiciary.

The Human Rights Campaign denounced Hart’s ruling. “It is clear that including both married spouses’ names — regardless of whether they are same-sex or opposite sex — on a child’s birth certificate is exactly the kind of benefit of marriage that the U.S. Supreme Court ruled should be extended to same-sex couples,” said HRC senior legislative counsel Kate Oakley in a press release. “This disappointing ruling from the Arkansas Supreme Court is a clear violation of equal protection for married, same-sex couples, as affirmed by the U.S. Supreme Court in Obergefell, and it is a deliberate attempt to undermine the rights of couples who have been guaranteed equality under the law when it comes to marriage.”