By Katherine Sellgren
BBC News education reporter at the ATL conference
Giving parents money to set up schools has become a political battleground
A teachers' leader has described Conservative plans to allow parents to set up and run their own schools in England as "barking mad".
Mary Bousted, from the Association of Teachers and Lecturers, claimed the move could lead to some pupils being taught creationism instead of literacy.
She said the Tories had not addressed how it would benefit poorer children.
Shadow Schools Secretary Michael Gove insisted the policy aimed to "tackle education inequality".
Dr Bousted said serious questions remained unanswered about how schools set up by parents or other groups, funded by the government, yet free from its control, would work.
"One of the barking mad ideas is that all state schools will have a very rigid national curriculum and the free schools will be able to teach what they want.
"Are we going to set up schools where they're going to be taught that creationism is a scientific fact and there will not be a proper emphasis on literacy and numeracy?
"The idea that the market will sort it out is not good enough - we can't leave schools to parental prejudices."
Wayne versus Henry
Dr Bousted said children were not commodities and the state had a "duty and responsibility" to educate all children.
"I'm still very concerned what's going to happen with the over-provision of schooling - schools have fixed costs, they have heating and lighting.
"What's going to happen to those schools with Wayne and Sharon in, who are going to lose teachers, who are going to lose funding, who are going to lose money, because Henry and Henrietta are going to school in the semi-detached Edwardian house down the road, with the woollen blazers and the felt grey hats?"
In her closing speech to the ATL conference in Manchester, she said: "No one is fit to be the custodian of the nation's children unless they seek first and foremost to even up the odds produced by accident of birth."
But Mr Gove said all the evidence from Sweden - where non-profit and profit-making groups can set up schools funded by the government, but free from its control - showed free schools raised attainment.
"The driving moral purpose behind Conservative education reform is to tackle education inequality. The Conservatives will create a new generation of independent, free, and non-selective schools.
"This will give all parents, not just the rich, what they want - smaller schools with smaller classes, good behaviour, great teachers and restored confidence in the curriculum."
His policy was also criticised by the Schools Secretary Ed Balls, who addressed the ATL conference on Wednesday.
Mr Balls said it was irresponsible to tell parents' groups they could set up their own schools, yet not say how it would be paid for.
"He's like Santa Claus offering a free lunch to every parent who wants to set up a school," he said.
The Liberal Democrats have also criticised the free schools plan, describing the policy as "misguided" and "costly".
They have said the idea that standards will rise across the country if it is made easier for new providers to open schools "is a nonsense".