JK Rowling's agency has refused demands to issue a public statement in support of transgenderism after recent comments on the issue by the Harry Potter author.
Authors Fox Fisher, Drew Davies and Ugla Stefanía Kristjönudóttir Jónsdóttir, also known as Owl Fisher, have now quit the Blair Partnership, which represents Rowling.
They said in a joint statement on Medium that they had reached out to the agency "with an invitation to reaffirm their stance to transgender rights and equality".
"After our talks with them, we felt that they were unable to commit to any action that we thought was appropriate and meaningful," they said.
"Freedom of speech can only be upheld if the structural inequalities that hinder equal opportunities for underrepresented groups are challenged and changed."
A spokeswoman for Blair Partnership told the Guardian that the agency was not prepared to have staff "re-educated" over Rowling's comments.
Despite a fierce backlash, Rowling has stood by her comments, which were made in response to an article that referred to "people who menstruate".
"I'm sure there used to be a word for those people. Someone help me out. Wumben? Wimpund? Woomud?" she said on Twitter.
She later defended her views in an essay on her website in which she said that many women are "justifiably terrified" of trans activists.
"I know this because so many have got in touch with me to tell their stories. They're afraid of doxxing, of losing their jobs or their livelihoods, and of violence," Rowling said.
"But endlessly unpleasant as its constant targeting of me has been, I refuse to bow down to a movement that I believe is doing demonstrable harm in seeking to erode 'woman' as a political and biological class and offering cover to predators like few before it.