A charity worker who lost her job after posting tweets questioning government plans to reform gender recognition laws has lost her case at employment tribunal.
Maya Forstater, 45, said that the ruling against her "removes women's rights and the right to freedom of belief and speech".
She was a visiting fellow at the Centre for Global Development (CGD) but after she expressed the view on Twitter that "men cannot change into women", her contract was not renewed in March.
She argued that her beliefs about biological sex should be protected under the 2010 Equality Act and launched a legal challenge that was financed through crowdfunding.
The Central London employment tribunal disagreed with her, however, with employment judge James Tayler ruling on Wednesday that her views did "not have the protected characteristic of philosophical belief".
He further said that the language in her tweets was "offensive and exclusionary".
In a 26-page judgement, he said: "I conclude from ... the totality of the evidence, 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.
"The approach is not worthy of respect in a democratic society."
Responding to the ruling on her CrowdJustice crowdfunding page, Forstater said she felt "shock and disbelief" after reading the judgement.
"My belief ... is that sex is a biological fact, and is immutable," she said.
"There are two sexes, male and female. Men and boys are male. Women and girls are female. It is impossible to change sex. These were until very recently understood as basic facts of life by almost everyone."
She expressed concerns that more people who share her views will suffer if they express them publicly.
"This judgment removes women's rights and the right to freedom of belief and speech," she said.
"It gives judicial licence for women and men who speak up for objective truth and clear debate to be subject to aggression, bullying, no-platforming and economic punishment.
"I will consider the judgment closely with my legal team to determine what can be done to challenge it."
Forstater was represented by Peter Daly, of Slater and Gordon, who said: "The significance of this judgment should not be downplayed.
"Had our client been successful, she would have established in law protection for people – on any side of this debate – to express their beliefs without fear of being discriminated against."