In the other two cases, gay workers said they were fired by their employers because of their sexual orientation.
The court will decide whether the Civil Rights Act of 1964, which bans discrimination in the workplace on the basis of race, color, religion, sex, or national origin, also applies to sexual orientation and gender identity.
In the absence of a ruling from the top US court, lower courts have issued contradictory decisions.
The case is likely to be heard in the fall with a ruling issued next year.
