A body representing teachers in Northern Ireland has said that criticism of how history is taught "over-states the situation and does a disservice to the many excellent, risk-taking teachers in NI".
The History Teachers Association (HTANI) said a Parallel Histories study that was released earlier this week was "based on an informal survey, not official figures".
The survey suggested that the curriculum itself could be dividing schools along the lines of the conflict. It showed that the overwhelming majority of Catholic schools teach a more modern unit, which covers 1965-98 and majors on the civil rights campaign and the Troubles.
But just under half of state schools teach the 1920-49 period instead, which features the Second World War.
The survey was carried out by two Year 11 classes in Stoke-on-Trent and Lancaster during lockdown.
The study was conducted under the auspices of the Parallel Histories charity. Its founder Michael Davies revealed to The Guardian that a definitive bias along denominational lines was found.
Four out of 10 state schools, for which data was available, taught the earlier 1920-49 unit, compared with just one in 10 Catholic schools.
In response to the study, HTANI president Dr Alan McCully, on behalf of the association, said that while there was "some substance" to criticism of the GCSE History curriculum there were also a number of "misconceptions".
"Avoidance of sensitive and controversial issues has been common in NI and is not confined to history teachers.
"The reality is that schools from Protestant backgrounds have been switching to the later Troubles period over time as the political situation has evolved."
Dr McCully wrote that presenting pupils with opposing "Protestant" and "Catholic" narratives was a "blunt and dated" approach.
"Thankfully, we now advocate a more complex and nuanced stance, which recognises shades of opinion across the unionist/nationalist continuum and beyond, thus better preparing young people to understand the past and, crucially, to make connections with the present.
"They come to realise that both then and now individuals think for themselves and that views can change over time."
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This year nearly 7,000 students were supposed to sit the history GCSE History exam in Northern Ireland, and if they'd been able to, they would have been examined on either the history of Northern Ireland 1920-49, or the history of Northern Ireland 1965-98.