Schools are dropping controversial subjects from history lessons - such as the Holocaust and the Crusades - because teachers do not want to cause offence, Government research has found.
The way the slave trade is taught can lead white children - as well as black pupils - to feel alienated, according to the study by the Historical Association.
And a lack of factual knowledge among teachers, particularly in primary schools, is leading to "shallow" lessons on emotive and difficult subjects.
Some teachers have even dropped the Holocaust completely from lessons over fears that Muslim pupils might express anti-Semitic reactions in class.
And one school avoided teaching the Crusades because its "balanced" handling of the topic would directly contradict what was taught in local mosques.
The report, funded by the Department for Education and Skills, said: "Teachers and schools avoid emotive and controversial history for a variety of reasons, some of which are well-intentioned.
"Staff may wish to avoid causing offence or appearing insensitive to individuals or groups in their classes.
"In particular settings, teachers of history are unwilling to challenge highly contentious or charged versions of history in which pupils are steeped at home, in their community or in a place of worship."
The researchers gave the example of one history department in a secondary school in a northern city which decided not to teach the Holocaust as a topic for GCSE coursework.
The report said the teachers feared confronting "anti-Semitic sentiment and Holocaust denial among some Muslim pupils". Christian parents at another school complained over the way the Arab-Israeli conflict was taught.
