In the summer of 1989, U.S. senators debating the Americans with Disabilities Act excluded behavior they deemed immoral from the ADA's protections, including “transvestism, transsexualism, pedophilia, exhibitionism, voyeurism, gender identity disorders not resulting from physical impairments, or other sexual behavior disorders,” according to the text of the law.

That portion of the ADA hasn't been challenged until now.

Kate Lynn Blatt, a transgender woman who was fired from her job at Cabela's, filed a discrimination suit last summer making claims under both the ADA and Title VII of the Civil Rights Act, which is more often used in cases like this one.