The Justice Department outlined, in a Friday court filing, its reasons why transgender discrimination in the workplace is illegal under federal law.

The filing is related to an upcoming Supreme Court case involving a transgender funeral worker Aimee Stephens, who was fired from her position after announcing her transition.

Per the Justice Department's brief, the word "sex" solely refers to the biological sex of an individual.

Earlier this week, Bloomberg Law reported that the Justice Department was seeking to persuade the Equal Employment Opportunity Commission to support its stance on LGBTQ discrimination in the case.

The Supreme Court will hear Stephens' case on October 8.

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The Trump administration outlined in a court filing on Friday why it believes transgender discrimination is legal in the workplace under federal law — a broad setback in LGBTQ rights since the Obama administration.

The 1964 Civil Rights Act states that employers also can't discriminate based on sex, race, color, religion, and national origin. The Justice Department under the Trump administration, is arguing that workplace discrimination based on sex does not apply to transgender workers.

The filing is related to an upcoming Supreme Court case involving a transgender funeral worker Aimee Stephens who was fired from her position after announcing her transition.

Per the Justice Department's brief, the word "sex" solely refers to the biological sex of an individual.

"In 1964, the ordinary public meaning of 'sex' was biological sex. It did not encompass transgender status,

which Stephens and the Sixth Circuit describe as a disconnect between an individual's biological sex and gender identity," the court filing stated. "In the particular context of Title VII ... it was especially clear that the prohibition on discrimination because of 'sex' referred to unequal treatment of men and women in the workplace."

Read more: The Justice Department wants the Supreme Court to be told it's ok for businesses to discriminate against transgender employees

The Obama administration's Justice Department had previously asserted that Title VII did protect transgender workers and would argue as such in court. The Equal Employment Opportunity Commission has upheld the Obama-era rule since then. This was exemplified in last year's 3-o decision in a lower court, which ruled in favor of Stephens.

The court ruled that "discrimination against employees, either because of their failure to conform to sex stereotypes or their transgender and transitioning status, is illegal under Title VII" of the federal employment rights law.

However, the DOJ under the Trump administration argued that Congress did not have the LGBTQ community in mind when passing the 1964 law. Earlier this week, Bloomberg Law reported that the Justice Department was seeking to persuade the EEOC to support its stance that it would not be in violation of the law for businesses to discriminate against transgender employees.

"As it stands, Title VII prohibits treating an individual less favorably than similarly situated individuals of the opposite sex," the Justice Department contended in the court filing. "It simply does not speak to discrimination because of an individual's gender identity or a disconnect between an individual's gender identity and the individual's sex."

The Supreme Court will hear Stephens' case on October 8.