Attempts by the Government to secure a compromise over the controversial Section 28 were rejected by teachers' leaders and opposition MPs last night who called them patronising and ineffective.
Although new guidelines on sex education were welcomed by the Church of England and Catholic leaders, some teaching unions warned the wording of the document amounted to Section 28 by another name and it would leave teachers facing the threat of legal action.
Teachers' leaders are worried about a clause saying there should be "no direct promotion of sexual orientation".
Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, said the proposals were like "section 28 reinstated".
Children will be required to "learn the significance of marriage and stable relationships as key building blocks of community and society", under an amendment to the Learning and Skills Bill tabled by David Blunkett, the Education and Employment Secretary.
Bishops are expected to drop their opposition to repeal of Section 28, which bans councils from promoting homosexuality, when the Local Government Bill returns to the House of Lords in July.
But the Tories, who joined with the bishops and some Labour peers to defeat the proposal last month, said they would "stick to our guns" and vote against the Government, despite the new pro-marriage guidelines. Although ministers are quietly confident of victory, the crucial vote could be close.
Baroness Young, the Tory peer who led last month's Lords' rebellion, said the amendment did not go far enough because it would still be possible to promote homosexuality in schools. "This is a typical 1960s mishmash of a value-free society, put in front of children, which has caused a lot of the troubles we have today."
Under the guidelines, children will have to be protected from "inappropriate teaching and materials" and learn about the importance of marriage "for family life and for the bringing up of children".
Mr de Gruchy declared the guidelines "insulting, patronising, superfluous", adding: "We are in danger of going back to the American south. I would say things could be worse now because people have 33 pages of guidance to bite on.
"Schools already do an excellent job in moral education. They should be left to make their own judgements in a very sensitive area rather than risk insulting and alienating many people in their communities who may not fit the Government's preferred model."
John Dunford, general secretary of the Secondary Heads Association, said: "It is a difficult area and people have felt inhibited because of Section 28 and they will continue to feel inhibited. This has not made teaching sex education and relationships any easier.
Doug McAvoy, general secretary of the National Union of Teachers, said: "Teachers are having to pay the price for the Government's difficulties in the Lords. While I welcome the late addition of the reference to stable relationships in the guidance, legal and bureaucratic imposition is not the way to back teachers' judgements and meet pupils' needs."Reuse content