State Constitutional Challenges to Laws Defining Sex

Constance Van Kley is an assistant professor at the Blewett School of Law at the University of Montana. She was involved in her private capacity in the early stages of the Edwards v. Montana litigation.

Among the flurry of executive orders issued on day one of President Donald Trump’s second term was an order defining sex as binary — “not changeable and . . . grounded in fundamental and incontrovertible reality,” with a person’s sex determined at conception. The order claims to protect women from men, and it will likely serve as the basis for a wide range of federal policies affecting transgender persons, such as prison housing and access to public accommodations.

The executive order is not the only recent attempt to categorize humanity into two distinct, unnuanced categories based on reproductive capacity from the earliest stages of development. Three states — Kansas, Montana, and Tennessee — passed laws similarly defining sex in 2023. While the laws differ somewhat, all say that sex cannot be changed and is determined at birth. The Kansas law, passed over a gubernatorial veto, defines sex according to a person’s ability to produce eggs or sperm. The Tennessee law refers only to “anatomy and genetics,” and the Montana law describes sex as defined by both chromosomal makeup and egg or sperm production.

The legislatures of Alabama, Idaho, Iowa, Louisiana, Mississippi, North Dakota, Oklahoma, Utah, West Virginia, and Wyoming followed suit, passing similar laws beginning in mid-2024. And the governors of Indiana and Nebraska issued executive orders similarly defining sex as unchangeable and binary. This second wave of state laws and orders tends to focus on the gametes that a person will produce, as determined at birth. The Oklahoma law, for example, defines sex as “a natural person’s biological sex at birth” and “female” as “an individual who naturally has, had, will have, or would have, but for a developmental or genetic anomaly or historical accident, the reproductive system that at some point produces, transports, and utilizes eggs for fertilization.” These laws, like the recent executive order, are often pitched as — and sometimes even explicitly reference — providing enhanced protections for women.

Like the federal executive order, state laws defining sex are likely to have wide reach, potentially impacting sports participation, public bathroom access, nondiscrimination laws, and more. And, as is generally the case, there is no one-size-fits-all approach to the constitutional issues likely to arise in state litigation. But a few general principles may be applicable more broadly, as outlined in the first state trial court decision to find a law defining sex substantively unconstitutional and therefore void.

In Edwards v. Montana, a state court held Montana’s law defining sex was facially unconstitutional under the state constitution. It is not yet clear whether the state will appeal the decision to the Montana Supreme Court. As Edwards shows, state laws defining sex may be vulnerable to challenge under state constitutions for three reasons — more relaxed standing doctrines, specific provisions relating to privacy, and more robust protections against discrimination.

Laws defining sex often take a sledgehammer to the state code, incorporating binary definitions into multiple areas of law. For example, a law defining sex may have the effect of authorizing transgender discrimination, preventing people from amending their birth certificates, and preventing using the bathroom aligned with one’s gender identity. In federal courts, the burden falls on the plaintiff to attack the constitutionality of all aspects of a challenged law, making vague laws with diverse intrusions into individual liberties harder to challenge.

But state courts are more likely to be receptive to facial challenges to laws with wide-ranging effects. State constitutions rarely include “case or controversy” limitations on judicial power (the source of federal standing doctrine). And, although state courts tend to reflexively adopt federal separation of powers doctrines, state constitutions generally assign more power to state judiciaries, providing strong arguments to distinguish an increasingly cribbed federal judicial power. Thus, even in states that often follow federal standing doctrine, courts may reject strict limits on their authority to review a law’s constitutionality.

Along those lines the Edwards court rejected the federal standard for facial challenges. The challengers included two intersex persons, three transgender persons, and the Montana Two Spirit Society (an organization that advocates for Native American LGBTQ+ people). The state argued the plaintiffs had failed to explain how each aspect of the law would affect them, but the court rejected the state’s proposed approach.

The court found the intersex plaintiffs were effectively defined out of the law, sufficient to show constitutional injury. For example, one of the plaintiffs was a woman with Complete Androgen Insensitivity Syndrome — meaning she has XY chromosomes and was born with internal testes but has female external genitalia. Under the Montana law, she is male. And because the law imports its definitions of sex into state nondiscrimination law, she has no protection if an employer discriminates against her as a woman or as an intersex person. As absurd a result as this may be, it is a natural reading of the law. The court determined it was enough to trigger constitutional review of the definitions.

State constitutions may constrain legislation seeking to define individuals according to biological sex in other ways as well. Privacy and equal protection rights are particularly relevant.

While the modern U.S. Supreme Court rejects the idea of a generalized “right to privacy,” state courts, applying their own constitutions, view privacy rights less narrowly. At least 11 states have express constitutional rights to privacy. Others protect medical decision-making in at least some contexts, and still others have found an implicit right to privacy that exceeds the federal floor. This matters: Laws defining sex prevent people from exerting control over deeply private choices, from marking a sex on a driver’s license to deciding which bathroom to enter. And they place government in a position to verify or contest a person’s sex — a task that may require medical examinations and genetic testing. Thus, in Edwards, the trial court concluded that the Montana law “takes away Plaintiffs’ ability to define or identify themselves,” interfering with their right to make decisions regarding their “body and psyche.”

Finally, state protections against sex discrimination will likely factor into future challenges to state laws defining sex. State anti-discrimination and equal protection clauses can be stronger and more specific than the federal 14th Amendment. A majority of state constitutions include some protection against sex-based discrimination. Because it relied on the right to privacy, the Edwards decision did not address whether the Montana law was inconsistent with the state constitution’s express protection against sex-based discrimination. But the current movement to define sex cannot change the meaning of preexisting constitutional provisions, which may prohibit treating people differently when their sex, as defined by the legislature, does not align with their gender as they define it.

Interestingly, some of the state laws defining sex refer to court rulings or confusion about what sex discrimination truly is, presumably taking issue with courts for finding legal protections for transgender persons. For example, the Alabama law states that “[i]nconsistencies in court rulings and policy initiatives regarding sex discrimination and common sex-based words have endangered women’s rights and resources.” Legislators are likely referring not to state precedent but to Bostock v. Clayton County, a U.S. Supreme Court case finding that firing someone “merely for being gay or transgender” violates the Civil Rights Act. Obviously, however, state legislators cannot change the interpretation of a federal statute, just as they cannot change the meaning of a state constitutional provision.

Suggested Citation: Constance Van Kley, State Constitutional Challenges to Laws Defining Sex, Sᴛᴀᴛᴇ Cᴏᴜʀᴛ Rᴇᴘᴏʀᴛ (May 15, 2025), https://statecourtreport.org/our-work/analysis-opinion/state-constitutional-challenges-laws-defining-sex