WASHINGTON – More than 200 companies urged the Supreme Court on Tuesday to apply the nation's job discrimination laws to sexual orientation and gender identity.

In three major civil rights cases the justices will hear when they return to the bench in October, the companies – which together employ more than 7 million workers and have more than $5 trillion in revenue – said "the U.S. economy benefits from a diverse workforce."

The cases from New York, Michigan and Georgia involve workers who claim they were fired because they were gay or transgender:

A New York skydiving instructor, Donald Zarda, said he was fired because he was gay. He has died, but his sister and life partner continue to press the case.

A Georgia county government employee, Gerald Bostock, alleged he was fired from his job as a child welfare services coordinator because he is gay.

A Michigan transgender woman, Aimee Stephens, said she was fired from the funeral home where she worked for six years as Anthony Stephens because of her transition.

A decision in the challengers' favor would mark an important step in the effort to protect the LGBT community from discrimination in employment, housing and public accommodations, advocates said.

"Laws forbidding sexual orientation or gender identity discrimination are not unreasonably costly or burdensome for business," the companies argued in legal papers submitted to the high court. "Only a uniform federal rule can enable businesses to recruit and retain, and employees to perform, at their highest levels."

Among the companies signing on: Amazon, Apple, Cisco, eBay, Facebook, Google, LinkedIn, Microsoft, Nike, Starbucks, Uber, Univision and two baseball teams, the San Francisco Giants and Tampa Bay Rays.

Other signers include AT&T, General Motors, Southwest Airlines, MGM Resorts, CVS, JPMorgan Chase, Prudential, Wells Fargo, Xerox, Goldman Sachs, Levi Strauss, Northrup Grumman, American Airlines, Walt Disney, Marriott, Hilton, Domino's and IBM.

Title VII of the 1964 Civil Rights Act bars discrimination based on sex, race, color, national origin and religion. It does not specifically address sexual orientation or gender identity.

Federal appeals courts are divided over the question of sexual orientation, and the Supreme Court agreed to hear two cases that came to opposite conclusions. The transgender woman in the Michigan case won in the lower court.

The LGBTQ rights movement had hoped to get the issue to the high court before Associate Justice Anthony Kennedy, the author of several landmark gay rights decisions, retired last summer. The cases will be heard in October before a court with five solid conservative justices and four liberals.