JK Rowling is facing a storm of criticism from the transgender community after coming out in support of a researcher who was sacked for stating that a person’s biological sex cannot be changed.

Maya Forstater, 45, was sacked from the Centre for Global Development, an international think tank, after posting a series of tweets that questioned the British government’s plans to let people declare their own gender.

Ms Forstater appealed the dismissal to an employment tribunal. But A London judge this week upheld her sacking, finding that:

“[Forstater] is absolutist in her view of sex and it is a core component of her belief that she will refer to a person by the sex she considered appropriate even if it violates their dignity and/or creates an intimidating, hostile, degrading, humiliating or offensive environment.”

On Thursday (local time), Rowling tweeted a response that said: “Call yourself whatever you like. Sleep with any consenting adult who’ll have you. Live your best life in peace and security. But force women out of their jobs for stating that sex is real?”

Dress however you please.
Call yourself whatever you like.
Sleep with any consenting adult who’ll have you.
Live your best life in peace and security.
But force women out of their jobs for stating that sex is real? #IStandWithMaya #ThisIsNotADrill

— J.K. Rowling (@jk_rowling) December 19, 2019

She included the now trending hashtag #IStandWithMaya and #ThisIsNotADrill.

The Harry Potter author is otherwise known for her liberal political views and many on Twitter labelled her a TERF (Trans Exclusive Radical Feminist).

Among those criticising her was the Human Rights Campaign, which tweeted: “Trans women are women. Trans men are men. Non-binary people are non-binary. CC: JK Rowling.”

A spokeswoman for Rowling said the author would make no further comments.

It’s not the first time she has run foul of the LGBTQI community, however.

In 2007, Rowling caused a stir when she said Albus Dumbledore, a key character in her Harry Potter novels, was gay. But the revelation only came after the final book had been published and with no explicit mention of his sexuality in the text.

She angered fans again in 2018 when Fantastic Beasts 2 director David Yates said the younger Dumbledore character would not be explicitly gay in the prequel film written by Rowling.

Ms Forstater, who raised more than $A160,000 through crowdfunding to pay her legal bills, said told the BBC she had been “blown away by the support and interest in her case”.

“All I ever wanted on this was for people to be able to talk about the policy questions around sex and gender identity in a normal, open, democratic way,” she said.

-with agencies