In a decision that could have potentially far-reaching consequences, the U.S. Supreme Court has said it will hear cases involving claims that sexual orientation and gender identity should be included under current federal protections barring sex discrimination.

One case involves a male employee who identifies as a woman and was fired from a funeral home for deciding to wear women's clothes to work.

John Bursch, vice president of appellate advocacy at the religious freedom legal group Alliance Defending Freedom, argued that the court should uphold current federal law.

"Neither government agencies nor the courts have authority to rewrite federal law by replacing 'sex' with 'gender identity'-a change with widespread consequences for everyone," he said April 22.

The U.S. Supreme Court on Monday said it would hear the cases in the upcoming court term, with decisions and opinions possible in 2020.

Alliance Defending Freedom is backing the funeral home at the center of one case, R.G. & G.R. Harris Funeral Homes v. Equal Employment Opportunity Commission (EEOC).

The family-owned funeral home, owned by Tom Roost, has operated since 1910 and now has several chapels.

In 2007 it hired a male employee who agreed to follow the company's policies, including its sex-specific dress code. The ADF summary of the case said the dress code is "crafted to emphasize professionalism and keep the focus on those mourning the loss of a loved one."

In 2013, the employee told Roost that he intended to begin dressing as a woman at work.

"Tom determined that allowing this would not be in the best interests of his clients processing their grief," Alliance Defending Freedom said on its website summary of the case. "He offered the employee a severance package, which the employee refused."

The employee, who now goes by Aimee Stephens, wrote to colleagues that year: "What I must tell you is very difficult for me and is taking all the courage I can muster... I have felt imprisoned in a body that does not match my mind, and this has caused me great despair and loneliness."

Stephens filed suit on legal grounds including Title VII of the Civil Rights Act of 1964, a federal law which bars discrimination on categories including race, religion, national origin and sex.

In 2016, the U.S. District Court for the Eastern District of Michigan backed the funeral home. However, the EEOC appealed the case, and the U.S. Court of Appeals for the 6th Circuit then ruled that the dress code was discriminatory against a male employee who identifies as a woman.

"It is analytically impossible to fire an employee based on that employee's status as a transgender person without being motivated, at least in part, by the employee's sex," said the appellate court, according to the New York Times. "Discrimination 'because of sex' inherently includes discrimination against employees because of a change in their sex."

Bursch, who served as solicitor general of Michigan from 2011 to 2013, said the funeral home wanted "to serve families mourning the loss of a loved one." He charged "the EEOC has elevated its political goals above the interests of the grieving people that the funeral home serves."

"Businesses have the right to rely on what the law is-not what government agencies want it to be-when they create and enforce employment policies," Bursch added.

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The Supreme Court accepted the funeral home case on the limited questions of whether Title VII bars discrimination against self-identified transgender people based on "their status as transgender" or "sex stereotyping" under a 1989 Supreme Court decision, Price Waterhouse v. Hopkins.

Alliance Defending Freedom's brief filed with the U.S. Supreme Court argued that the Sixth Circuit's interpretation "undermines the primary purpose for banning discrimination based on sex," namely to ensure equal opportunities for women and to eliminate workplace inequalities that have held women back.

If the lower court's interpretation holds, it said, employment reserved for women like playing basketball in the WNBA or working at a shelter for abused women "now must be opened to males who identify as women." Such a definition would also undermine Title IX efforts to advance women's participation in sports and educational opportunities, it said.

"Substituting 'gender identity' for 'sex' in nondiscrimination laws also threatens freedom of conscience," the ADF petition added, saying that such interpretations have forced doctors to participate in surgical efforts to alter sex "in violation of their deeply held beliefs" and best medical judgment.

"In sum, the Sixth Circuit ushered in a profound change in federal law accompanied by widespread legal and social ramifications," the legal group charged.

Two other cases, Bostock v. Clayton County, Georgia and Altitude Express, Inc. vs. Zarda, will also go before the Supreme Court. They were consolidated because of similar claims regarding employer discrimination on the basis of sexual orientation, National Public Radio reports.

The case Altitude Express, Inc. v. Zarda involves the late New York skydiving instructor Donald Zarda, who said he was fired because he was gay. He was fired after a female customer complained. She had voiced concerns about being tightly tied to Zarda during a tandem dive, and Zarda tried to reassure her by telling her he was "100% gay," the New York Times reports.

Zarda was killed in a skydiving accident in 2014 but his estate is continuing to pursue the case.

A divided 13-judge panel for the U.S. Court of Appeals for the 2nd Circuit ruled that the lawsuit could proceed.

Chief Judge Robert A. Katzmann, writing the court's majority opinion, said "sexual orientation discrimination is motivated, at least in part, by sex and is thus a subset of sex discrimination." Sexual orientation discrimination is "predicated on assumptions about how persons of a certain sex can or should be, which is an impermissible basis for adverse employment actions."

"(S)exual orientation discrimination-which is motivated by an employer's opposition to romantic association between particular sexes-is discrimination based on the employee's own sex," Katzmann's decision added.

The case Bostock v. Clayton County involves a Georgia child welfare services coordinator who said he was fired for being gay, the New York Times reports.

The 11th Circuit Court of Appeals in July 2018 issued an unsigned opinion citing a 1979 5th circuit court decision ruling that firing for homosexuality is not barred by Title VII.

Most federal courts do not consider sexual orientation discrimination to be a form of sex discrimination, the New York Times reports.

EEOC publications on the commission website hold that "sex stereotypes" like "the belief that men should only date women or that women should only marry men" constitute illegal discrimination on the basis of sex. They say that the 1964 civil rights legislation against sex discrimination in the workplace includes discrimination "based on an applicant or employee's gender identity or sexual orientation."

However, those opinions lack Congressional approval. Proposed legislation known as the Equality Act would add "sexual orientation" and "gender identity" as protected categories under federal law.

Critics have warned that the legislation explicitly rejects religious freedom protections and would open the gates to anti-discrimination lawsuits against religious believers and institutions who disagree with the bill's broad view of what constitutes LGBT discrimination.