A Christian teacher sacked over Facebook posts criticising sex education in schools has told an employment tribunal that she does not believe in the "modern ideas of gender fluidity and transgenderism".

Kristie Higgs, 44, is challenging her dismissal for gross misconduct by Farmor's School in Fairford, Gloucestershire. 

She was dismissed in January last year after the school received an anonymous complaint over two posts Mrs Higgs shared to her personal Facebook page - under her maiden name - in October 2018.

One post asked friends and family to sign a petition rejecting the new Relationships and Sex Education (RSE) curriculum, while the other linked to an article discussing the prevalence of transgender ideology in children's books in American schools. 

Her case is being heard at the employment tribunal in Bristol this week, where she is being represented by the Christian Legal Centre (CLC). 

The CLC argues that her dismissal was in breach of religious freedom and free speech laws.

"I believe that God created mankind as male and female and what he has created is good. He does not make mistakes. I therefore do not believe in the modern ideas of gender fluidity and transgenderism," Mrs Higgs told the tribunal on Monday, the Press Association reports.

"I did not think much about this issue until it was brought up in my younger son's primary school. I knew that there were cross-dressers and that the practice of cross-dressing had been expressly condemned in the Bible.

"People cannot change something that has been established by God, such as their identity as a man or a woman. I am aware that same-sex marriages are now recognised under UK law, but I believe that is contrary to God's law, which only recognises marriages between one man and one woman."

Mrs Higgs said she shared the posts on Facebook because she believed it was something her friends and family would be interested in. 

She added that she loved God and was prepared to follow the law of the land, but added that "it doesn't mean I can't disagree". 

"I just don't think what I did was wrong," she said.

Commenting ahead of the hearing, CLC chief executive Andrea Williams said that while many Christians had faced pressure for expressing similar views in their workplace, Mrs Higgs' case differed in that she was dismissed for sharing her views among friends on her personal Facebook account. 

"What Kristie shared on Facebook simply reflects the genuine and justified concerns of a parent about the sexual ideology currently being imposed on her own children and thousands of children across the UK," said Mrs Williams. 

"Kristie has not only lost her job, but her whole career is now tarnished with the accusation that for holding these views she is now a danger to vulnerable children.

"This is despite an exemplary record at the school and in her work with youth in the wider community. If Kristie does not win this case, due to one complaint, she will never be able to work with children again."