The Human Rights Campaign (HRC) is challenging a Tennessee law that prohibits transgender students, teachers, and school employees from using the bathrooms and locker rooms of their choice.

HRC, the nation's largest LGBT rights advocate, filed the suit on Tuesday.

Tennessee Governor Bill Lee, a Republican, signed the bill into law in May.

The Tennessee Accommodations for All Children Act (House Bill 1233) states that public schools must make a “reasonable accommodation” for a person who cannot or will not use a restroom or changing facility designated for their sex. The law makes clear that a “reasonable accommodation” does not “include access to a restroom or changing facility that is designated for use by members of the opposite sex while persons of the opposite sex are present or could be present.” Such accommodations include access to a “single-occupancy restroom.”

(Related: Judge blocks Tennessee anti-transgender law requiring restroom warning signs.)

Plaintiffs in the case are 14-year-old Alex and 6-year-old Ariel (not their real names) and their parents.

While attending the 7th grade, Alex was not allowed to use the bathroom of his choice due to school policy. He stopped drinking liquids at school to avoid having to use the restroom instead of using a private bathroom.

After attending a private school the last year, Alex will start attending a public high school in the fall.

Ariel, who began her social transition 4 years ago, attended kindergarten without incident. But in the fall, she'll be subject to the new law as she begins the 1st grade at a different school.

Both parents say they are considering moving to another state for their children's well-being.

In its lawsuit, HRC argues that the law violates Title IX and the Equal Protection and Due Process Clauses of the U.S. Constitution.

The U.S. Supreme Court last month refused to hear a case involving a Virginia student who was denied use of the bathroom of his choice. The high court's decision leaves in place a lower court's ruling that sides with the student.

(Related: Supreme Court declines to hear Gavin Grimm case, leaving transgender victory to stand.)