The U.S. Department of Education released a resolution plan Thursday afternoon, alleging that Denver Public Schools violated Title IX, the federal law against sex-based discrimination in education, by creating all-gender bathrooms and allowing students to use facilities that matched their gender identity instead of their biological sex.

The U.S. Department of Education’s Office for Civil Rights opened an investigation in January, centering on Denver’s East High School. District officials later converted a restroom for girls to an all-gender bathroom, which they said violated federal standards.

The Office for Civil Rights launched the investigation after the district changed a multi-stall restroom for girls to an all-gender bathroom. Federal officials said the school’s action was not in compliance with Title IX.

According to the resolution, district leaders made the decision even though they were aware the change could violate Title IX and create an unequal, unfair environment. They also did not address concerns raised by students and parents at the school about privacy and safety after the decision was made.

A second all-gender bathroom was later opened on the same floor. District officials have also said that all students have access to multiple restrooms on the same floor. They have also said students still have access to sex-segregated bathrooms at the school, as well as single-stall, all-gender bathrooms.

The department’s findings and proposed resolution plan were released Thursday. In the plan, the federal government gives the district four conditions they would have to fulfill in 10 days in order to avoid enforcement action.

The district would have to:

Change all all-gender multi-stall restrooms back to single-sex facilities.

Cease policies that allow students to use bathrooms or other intimate facilities that are not aligned with their biological sex.

Change all Title IX policies and guidance to include “biology-based definitions” for the terms “male” and “female.”

Send out a memorandum to schools clarifying that Title IX “requires school districts to ensure that students can use the intimate facilities that correspond to their biological sex while also protecting students’ privacy, dignity, and safety, and are readily accessible to students of both sexes.”

The resolution plan warns that if the district does not meet those conditions, the department could take action. That could include the withholding of federal funding.

In a statement, Acting Assistant Secretary for Civil Rights, Craig Trainor, said the district’s decision to convert the bathroom was in violation of Title IX because it “fail[ed] to provide students equal access to facilities” and also fostered a “hostile environment.”

“DP SCHOOLS VIOLATED TITLE IX BY CONVERTING A SEX-SEGREGATED RESTROOM DESIGNATED FOR GIRLS INTO AN ‘ALL-GENDER’ FACILITY AND BY ALLOWING STUDENTS TO USE THE HIGH SCHOOL’S INTIMATE FACILITIES ON THE BASIS OF THEIR GENDER IDENTITY RATHER THAN THEIR BIOLOGICAL SEX,” Trainor wrote in a statement.

“Denver is free to endorse this self-defeating gender ideology, but it is not free to accept federal taxpayer funds and harm its students in violation of Title IX,” he added. “The Trump Administration will work relentlessly to hold accountable school districts that harbor the ideological fanatics and policies that sully students’ educational experience with sex discrimination.”

District leaders have said the decision to create an all-gender bathroom was made by students as part of an effort to address student needs while also ensuring student safety and privacy. A spokesperson for the district said officials added 12-foot-tall partitions around toilets in the all-gender bathrooms in order to maintain privacy and security.

Denver Public Schools has not yet released a public statement in response to the resolution plan but has previously said it was providing a variety of restroom options for students, including single-stall, all-gender bathrooms for those who want more privacy.

The case in Denver is part of a larger national debate over how schools address gender identity. In March, President Donald Trump signed an executive order barring transgender girls from playing on sports teams that do not align with their biological sex.

Republican lawmakers in Congress have also been seeking to restrict transgender students from using bathrooms or playing on sports teams that do not match their biological sex.

The Department of Education has been involved in several other cases involving gender identity policies at schools and universities. This week, the department said that George Mason University broke federal law by using unlawful diversity, equity, and inclusion (DEI) practices, in violation of Title VI.

Denver Public Schools now has to decide whether to meet the demands of the federal government and withdraw its all-gender bathroom policies or face enforcement action.

The district will have to publicly respond to the Education Department’s resolution plan within the next 10 days.