A judge has ruled that a Montana law defining sex strictly as male or female is unconstitutional.

MISSOULA, Mont. (AP) — On Tuesday, a Montana law defining “sex” exclusively as male or female was struck down by a judge, and deemed unconstitutional.

District Court Judge Shane Vannatta of Missoula ruled that the law, enacted last year, violated the state constitution because its legislative description failed to clearly outline its purpose.

Plaintiffs, including transgender, nonbinary, and intersex individuals, contested the law, similar to statutes in Kansas and Tennessee, arguing it denies legal recognition and protections to gender-nonconforming people. Judge Vannatta did not address this argument, but rather focused on the bill's title, which did not clarify whether “sex” referred to sexual intercourse or gender, nor did it specify that "female" and "male" would be defined in the bill's content.

“The title does not provide adequate notice of the legislation's character, thus protecting against deceptive or misleading titles,” Vannatta stated.

The law, sponsored by Republican Sen. Carl Glimm, was passed during a legislative session that also included a ban on gender-affirming medical care for transgender minors and the expulsion of transgender lawmaker Democratic Rep. Zooey Zephyr from the House floor after a protest against Republican lawmakers who had silenced her.

Sen. Glimm argued the law was necessary following a 2022 court ruling allowing transgender individuals to change the gender markers on their birth certificates.

Republican Gov. Greg Gianforte’s spokesman, Sean Southard, defended the law, stating that it enshrined a long-recognized, commonsense definition of sex.

“Words matter. This administration is committed to ensuring words have meaning, unlike this judge, who seems to need a dictionary to distinguish between a noun and a verb,” Southard remarked.

Emilee Cantrell, spokeswoman for the Montana Attorney General's Office, affirmed the office’s commitment to defending a law that "reflects scientific reality."

The American Civil Liberties Union of Montana celebrated the ruling.

“Today’s ruling is an important affirmation of the protections the Montana Constitution provides for legislative enactments," stated the group's legal director, Alex Rate.