A federal judge in Denver has denied a motion to dismiss a lawsuit against Fort Collins that claims an ordinance that bars women from exposing their breasts in public violates the Constitution and is rooted in outdated puritanical values and discrimination.

U.S. District Judge R. Brooke Jackson said that the plaintiffs, Free the Nipple, an association of Colorado residents who advocate for gender equality, the group’s founder Brittiany Hoagland and Samantha Six, a group member, have “at the very least adequately stated a claim under the Fourteenth Amendment Equal Protection Clause.”

Under that amendment, Free the Nipple alleges that Fort Collins’ ordinance is unconstitutional because a difference between the sexes on which it is premised is “used to perpetuate stereotypes about girls and women,” namely that society considers they and their breasts primarily objects of desire.

The judge did dismiss a second claim in the association’s suit based on the First Amendment, a claim that the message of their nudity is part of their protest’s message about “the allegedly sexist nature of certain laws.”

In that case, he said that public nudity is not inherently expressive of any particular message.

“This is a great victory for women’s rights and equality under the law,” David Lane, lawyer for Free the Nipple, said in an email Thursday.

The Fort Collins City Attorney’s Office welcomed the partial dismissal, on the plaintiff’s First Amendment claim, and said it looks forward to arguing against the plaintiff’s remaining claims.

“The city is glad to see that the judge has narrowed the issues in this case by dismissing the First Amendment claim,” said City Attorney Carrie Daggett. “As the case moves forward to the hearing on the motion for preliminary injunction, we look forward to the opportunity to present evidence supporting the city’s position that the other two claims are also without merit.”

Hoagland brought the ordinance to the attention of the Fort Collins City Council last year. She wanted a change made to the language so that men and women would be free to show their breasts in the city.

The Council rejected the idea but approved tweaking the current law to allow breastfeeding and clarify how the ordinance applies to children younger than 10. That change defined the breast as beginning at the top of the nipple.

Section 17-142 of the Fort Collins code of ordinances discriminates against women by “making it a crime to show their breasts and/or nipples in any place where they might be viewed by others while allowing boys and men to show their breasts and/or nipples at any time or place without fear of arrest or prosecution,” the lawsuit said.

The group believes that any law containing language to the effect of “women are prohibited from” is sexist and, therefore, unconstitutional.

The modified version “continues to criminalize women who appear at public places with their breasts and nipples exposed,” the lawsuit said.

Thirty states, as well as Denver, Boulder, and New York, have recognized a woman’s right to appear topless in public, the suit says.

The lawsuit asks for an injunction to stop enforcement of the law, and declare it unconstitutional.