Around the country, high schools are increasingly confronting a thorny issue: Should transgender students be allowed into the locker room?

And increasingly, the federal government is stepping in to provide an answer: Schools must give trans students full locker room access.

Or else.

On Monday, the Obama administration again weighed in on the issue with the release of a report slamming a suburban Chicago public school district for not providing a transgender student with access to the girls’ locker rooms.

The report, which caps a two-year investigation, found that Township High School District 211 in Palatine, Ill., unfairly denied the transgender teenager — who was undergoing hormone therapy but had not undergone gender reassignment surgery — access to school facilities in violation of Title IX, that bars discrimination in federally funded education programs, causing her “isolation,” “ostracism” and at least one “tearful breakdown.”

“The denial of access has also meant that, in order to satisfy her graduation requirements and receive a high school diploma, Student A has had no other option but to accept being treated differently than other students by the District,” according to the 14-page report from the U.S. Department of Education’s Office for Civil Rights (OCR).

The student, who has not been publicly named, rejoiced at the report’s release.

The federal ruling “makes clear that what my school did was wrong,” she said in a statement to the American Civil Liberties Union of Illinois, which has backed her.

“This decision makes me extremely happy — because of what it means for me, personally, and for countless others,” she said. “The district’s policy stigmatized me, often making me feel like I was not a ‘normal person.’ ”

The school district now has 30 days to reach an agreement with authorities or risk losing up to $6 million in federal funding. The case could also be referred to the Department of Justice.

But district officials did not back down on Monday, insisting that they “remain strong in our belief that the District’s course of action … appropriately serves the dignity and privacy of all students in our educational environment.”

The school district standoff in Illinois comes at a time of nationwide debate over the rights of transgender individuals. Around the country, the movement for transgender rights has had recent success. Nearly half of all U.S. states — including Illinois — now prohibit discrimination against transgender people, with scores of cities following suit.

The much-publicized transition of celebrity and Olympic gold medalist Caitlyn Jenner has also put an unprecedented spotlight on the issue of transgender rights.

But the movement has also been met with resistance.

In Houston, the city council narrowly approved new protections for transgender people and other minorities in May 2014. But a fierce backlash against the law, including protests by local pastors, forced a referendum on the issue.

On Tuesday, Houstonians will take to the polls to decide whether the protections stay in place.

Nowhere has the battle over transgender rights been fiercer, however, than in public schools — especially their bathrooms and locker rooms.

In states around the country, transgender students have fought for the right to use their high school facilities, with mixed results. In Virginia, a transgender teen is suing the Gloucester County School Board for the right to use the boys’ restroom. In Southern California, two trans students recently won settlements with separate school districts over alleged harassment and unequal access.

The Obama administration has responded by supporting the transgender students in the Virginia and California cases. The Education Department and the Justice Department both have issued decisions arguing that transgender students must be given full access to bathrooms and locker rooms. The rulings are in line with the administration’s broader backing of transgender rights, including its recent decision to allow transgender members to serve openly in the military.

But in the case of high school locker rooms, activists and the Obama administration are up against even greater opposition.

Even more than bathrooms, where individual stalls provide some privacy, locker rooms have long provided a perfect storm of sensitive conditions: hormonal teenagers, naked bodies and a communal setting.

Now the push for greater transgender rights has merely shifted the so-called “Bathroom Wars” to the locker room.

This summer, an uproar in the American heartland cemented the locker room’s new status as the locus of social anxiety over teenage students being exposed to the opposite sex. In the small town of Hillsboro, Mo., transgender teen Lila Perry was allowed access to her school’s facilities this semester, only to face protests from her fellow students. (Perry has not filed suit.)

Many school districts opposed to the idea of allowing transgender students full access to locker rooms, including District 211 in Palatine, Ill., argue that doing so would put the interests of a few students over the privacy rights of the rest of the school.

But often the opposition appears to boil down to a desire to control teenage sexuality, or pretend it doesn’t exist.

In Missouri, the parent leading the opposition to Perry’s locker room access said he became involved after learning that a female student had encountered “an intact male” in the girls’ locker room.

Even in Palatine, Ill., a suburb of one of the country’s most liberal cities, the locker room standoff has at times descended into innuendo.

“Boys and girls are in separate locker rooms — where there are open changing areas and open shower facilities — for a reason,” District 211 Superintendent Daniel Cates said in a statement issued Monday, without identifying that reason.

“Permitting [the transgender student] to be present in the locker room would expose female students to being observed in a state of undress by a biologically male individual,” the school district argued, according to the report. “[G]ranting [her] the option to change her clothes in the girls’ locker room would expose female students as young as fifteen years of age to a biologically male body.”

That Palatine is the site of a scuffle over transgender rights is, unto itself, a sign of how hotly contested the issue continues to be in America.

As the OCR admitted in its report, District 211 is actually pretty progressive on transgender rights.

“OCR’s investigation revealed that, except with respect to locker room access, the District has treated Student A consistent with her gender identity as a girl,” according to the report. “This includes identifying Student A by her female name and with female pronouns, providing her with full access to all girls’ restrooms, and allowing her to participate in girls’ interscholastic athletics.”

But the report also found that the district violated federal law by denying the transgender student access to the school’s locker rooms, while also requiring her to take physical education classes.

“The District has required Student A to use separate restroom facilities, including facilities that are not comparable to those provided other students,” OCR investigators found. This exclusion had wide-ranging effects on the student. She was forced to change in the nurse’s office or use a private bathroom that was unlocked every day just for her, causing “isolation” and “ostracism.” Her efforts to hide her unequal treatment only resulted in further embarrassment, such as when she showed up to PE class late or in uniform when the rest of the class had been told to remain in street clothes. On the few occasions that she had to enter the locker room to rent a uniform or store something, she was reprimanded.

Perhaps the harshest consequences came from her involvement in one of her high school’s athletic teams, however. Because the transgender student wasn’t allowed to change with her teammates, she missed out on pre-game huddles, “girl talk” and other chances to bond, the report found. On the four occasions she did enter the locker room to chat before important games, “four girls and one parent complained” to the coach. When the coach chastised her, the transgender student experienced what the coach called a tearful “breakdown.”

The exclusion snowballed into her being left out of team activities and even suffering “disparaging treatment by members of her athletic team that appeared on social media,” according to the report, which also noted that the student had suffered “harassing comments in middle school when she used the boys’ locker rooms.”

When the student first complained to her principal in late 2013 that “she wanted to be a girl like every other girl,” she came away “crushed” that “the School did not accept her as female.”

She filed a complaint with OCR in December of 2013, setting off almost two years of investigations and failed negotiations that ended on Monday.

During that time, the school district’s stance has shifted slightly. Last month, her high school installed privacy curtains in the PE locker room.

“The solutions proposed by District 211 included multiple privacy stations in the locker rooms designed to provide privacy to any student while ensuring the full integration of transgender students in educational programs and activities,” Cates said on Monday. “Individualized, supportive approaches such as the ones proposed by District 211 have been implemented successfully in other schools.”

That wasn’t nearly enough for OCR. First, the swimming and athletic locker rooms remained unchanged and, therefore, inaccessible for transgender students, according to its report.

More importantly, the school district still demanded that the transgender student use the privacy curtains.

In contrast, OCR argued that requiring transgender students to use the privacy curtains was still unfair. Instead, any student could use the privacy curtains for whatever reason.

“Those female students wishing to protect their own private bodies from exposure to being observed in a state of undress by other girls in the locker rooms, including transgender girls, could change behind a privacy curtain,” according to the report. (For her part, the transgender student indicated she would use the curtains.)

The report concluded by giving the school district 30 days to “negotiate an agreement” to rescind “its discriminatory denial of access to the locker rooms” for transgender students or face up to $6 million in federal funding cuts and a possible criminal investigation by the Dept. of Justice.

Both sides have suggested the Palatine standoff is a test case for the entire country.

“If we do not stand up, this becomes precedent for everyone,” Cates told the Chicago Daily Herald last month. “OCR’s position has forced this to close far too soon.”

“They are telling a student that she can be with her friends at school but has to be relegated to a separate place to dress,” countered John Knight, the director of ACLU Illinois’ LGBT program and a member of the student’s legal team. “That’s just a horrible thing to do.”

Meanwhile, the locker room debate continues to sow division in the community and beyond.

“The remedy to the problem in District 211 is to reject the lies and accept the truth,” wrote local resident James Pittman II in a letter to the Daily Herald. “Males are male and females are female. Not only should male students not shower with female students, they shouldn’t be able to do the other things that current policy allows either. Why? Because they are male… If we are to survive as a culture and country, we must flee the chaos that comes with relative truth and once again embrace the ‘truths that are self-evident!'”

But his claims remain far from self-evident for many. Although the school district says 95 percent of people who have contacted it agree with its position, more than 350 area students had signed a petition supporting the transgender student as of Oct. 15.

“The truth is most students wouldn’t have a problem with this at all,” Jake Lytle, the Fremd High School senior who started the petition, told the Daily Herald.

Brian Harris, the superintendent of nearby District 220, agreed.

“Quite frankly, kids are really tolerant. Kids are amazing,” he told the Daily Herald. “This is not a kid issue. This is an adult issue.”