It's illegal for employers to discriminate against people who don't conform to gender stereotypes, the Missouri Supreme Court held Tuesday in a decision seen as a major victory for LGBTQ advocates.

The court ruled in a case involving a gay individual, Harold Lampley, who alleged that his employer discriminated against him because he didn’t exhibit stereotypically male behavior and apperance.

Missouri does not prohibit discrimination based on sexual orientation. But the court held that discrimination based on sex stereotypes is a form of sex discrimination, which Missouri’s Human Rights Act does prohibit.

“Sex discrimination is discrimination, it is prohibited by the Act, and an employee may demonstrate this discrimination through evidence of sexual stereotyping,” Judge George W. Draper III wrote for the court.

The Missouri Human Rights Commission had declined to investigate Lampley's claims because it assumed they were based on his sexual orientation.

A Cole County judge agreed with the commission and tossed the case, finding Lampley’s claims failed under a 2015 Missouri Court of Appeals case known as Pittman. The court in Pittman reasoned that sex stereotyping, like sexual orientation, is not specifically prohibited by the Missouri Human Rights Act.

But in its decision Tuesday, the Supreme Court called the circuit court judge’s reliance on Pittman misplaced because Lampley’s claim was not based on his sexual orientation.

“An employee who suffers an adverse employment decision based on sex-based stereotypical attitudes of how a member of the employee’s sex should act can support an inference of unlawful sex discrimination,” the court wrote. “Sexual orientation is incidental and irrelevant to sex stereotyping.”

Lampley worked in the child support enforcement division of Missouri’s Office of Administration. He claimed he was harassed and treated differently from other employees because his behavior didn’t conform to the stereotype of masculinity held by his employer and managers.

Lampley was joined in his suit by a friend and co-worker, Rene Frost, who claimed the office retaliated against her based on her association with Lampley.

“This is a significant decision because there are a lot of individuals in our community who happen to be gay or transgender or lesbian and they may not exhibit the stereotypes you would associate with somebody who was born with that particular sex,” said Jill Silverstein, a St. Louis attorney who represented Lampley and Frost.

Josh Pierson, a colleague of Silverstein's who also worked on the case, called the decision “a great result for our clients” and “a great result for the law and the state of Missouri and for Missourians generally.”

“The law clarified that the Human Rights Act prohibits discrimination on the basis of sex stereotyping and reinforces rights for all of us under the Human Rights Act,” Pierson said.

The court’s holding mirrors a similar result reached in October 2017 by the Missouri Court of Appeals in Kansas City when that court considered Lampley’s and Frost’s claims. The appeals court agreed that their claims were based not on their sexual orientation but on their sex.

The Supreme Court’s decision was one of two it handed down Tuesday bringing Missouri law in line with federal employment law and decisions in other states.

The other case involved a transgender student in the Blue Springs School District whose request to use the boy’s bathroom was denied.

“Members of the LGBTQ community should enjoy the same protections against sex-based discrimination as everyone else,” Tony Rothert, legal director of ACLU of Missouri, said in a statement. “Excluding LGBTQ individuals from legal protections was justified by outdated, destructive stereotypes and ignored the lived reality of thousands of people in our state.”

The ACLU filed friend-of-the-court briefs in both cases.

Steph Perkins, executive director of PROMO, an LGBTQ advocacy organization, said in a statement that he hopes the court's decisions “sends a message to the Missouri Legislature to clarify our Missouri Human Rights Act for LGBTQ individuals who already face higher rates of gender-based discrimination in our workplaces, homes and at school. LGBTQ Missourians need to be explicitly protected from discrimination under state law, and we urge them to act now.”

Like the appeals court, the Missouri Supreme Court drew on a long line of federal cases, including a 1989 U.S. Supreme Court decision, that have reached similar results.

In the Supreme Court case, a female senior manager with Price Waterhouse claimed she was denied a partnership in the firm because she was considered insufficiently feminine. The Supreme Court found that gender stereotyping could be a form of sex discrimination.

Lampley’s and Frost’s legal odyssey is not over. In overturning the circuit court’s decision, the Missouri Supreme Court directed the lower court to instruct the Human Rights Commission to issue right-to-sue letters to Lampley and Frost.

Silverstein, their attorney, said that her clients plan to sue their employer once that happens.

“It takes a lot of courage for individuals to step forward and pretty much expose themselves to the public and be willing to go into litigation,” Silverstein said. “Any party who decides to bring a discrimination lawsuit, that’s not an easy decision.”

Correction: Steph Perkins' gender was incorrect in an earlier version of this story.

Dan Margolies is a senior reporter and editor at KCUR. You can reach him on Twitter @DanMargolies .

Copyright 2020 KCUR 89.3. To see more, visit .