The U.S. government on Monday ordered a Chicago suburban high school district to give a transgender student full access to girls' locker rooms or lose federal funding.

The student, who has not been named, and the American Civil Liberties Union, which brought a complaint on her behalf, applauded the findings, while the school district called them "serious overreach."

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The district says transgender students may use their gender-identified locker room if they change and shower privately. The government said a separate changing place was discriminatory because it subjected the student to stigma and different treatment.

In mid-October the school district, with five high schools and two alternative high schools west of Chicago, defied the government, continuing to deny full locker-room access for the transgendered student.

Assistant U.S. Secretary for Civil Rights Catherine Lhamon said the high school was disobeying the law. "All students deserve the opportunity to participate equally in school programs and activities – this is a basic civil right," she said in a statement.

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"This decision makes me extremely happy – because of what it means for me, personally, and for countless others," the student said in a statement released by the ACLU. "The district's policy stigmatized me, often making me feel like I was not a 'normal person.'"

Last year, the district received $6 million in federal money contingent on compliance with non-discrimination rules.