London (CNN) "Harry Potter" author J.K. Rowling has come under fire for expressing support for a woman who lost an employment tribunal over comments she made on social media about transgender people.

J.K. Rowling attends the premiere of "Finding the Way Home" in New York on December 11, 2019.

Maya Forstater brought a claim against the Center for Global Development and CGD Europe, an international development think tank, after she lost her job as a researcher following comments on Twitter criticizing UK government plans to allow people to self-identify their gender.

Forstater does not believe that it is possible to change sex, and that men who have undergone gender reassignment surgery are still men -- even if the law recognizes them as women. "I don't think people should be compelled to play along with literal delusions like 'transwomen are women,'" she wrote in a private message to a co-worker that was cited in evidence in the case.

The tribunal, making a preliminary ruling in her case, determined that Forstater's views were not protected as a "philosophical belief" under the Equality Act 2010.

Details of the tribunal, held between November 13 and 21, were published Wednesday.