By Adam Easton
BBC News, Warsaw
More than 10,000 teachers have marched through the Polish capital to demand pay rises and demonstrate against the government's education policy.
Protesters say the new law would violate human rights
Gay rights groups joined to protest against plans to dismiss teachers who promote homosexual behaviour.
Ministers have said they are preparing a bill to ban what they called "homosexual propaganda" from schools.
The teachers were demanding both improved retirement benefits and the dismissal of the education minister.
They accuse Roman Giertych of ignoring teachers' groups and increasing intolerance.
The 36-year-old minister heads the small, right-wing and ultra-Catholic League of Polish Families party, which has been accused of being homophobic.
Mr Giertych and his deputy minister want to pass a law which would enable them to sack openly gay teachers or anyone who promotes homosexuality.
Teacher's union representative, Kalina Grzelak, said she was opposed the plan.
"We are going to use all the means to protect the freedom and to protect the tolerance in Poland because what we can see is simply intolerance and violation of human rights," she said.
Robert Biedron, who heads the Campaign Against Homophobia group, said the government's comments were worsening an already difficult climate for gays in Poland.
"The gay and lesbian community is isolated in Polish society, it is hated," Mr Biedron said.
"More and more gay people are victims of physical abuse so I'm very much concerned that Poland will become the Cuba or North Korea of Europe," he said.
Homophobia is common in this deeply Catholic country.
But Mr Giertych's views are seen by many here as radical and they have already got him into trouble in Brussels.
He can expect more of the same if the new law is considered to be discriminatory.