Teaching black boys separately would not necessarily improve their exam results, says an education specialist.
A US trial showed separating black boys improved exam results
Tony Sewell described the idea by the head of the UK's race watchdog, Trevor Phillips, as "almost a red herring".
"I don't really understand where that leads us in terms of achievement," said Dr Sewell, of the University of Leeds.
Last year 36% of Black Caribbean pupils in England got five or more C grades at GCSE. The national average is 52%.
Mr Phillips, of the Commission for Racial Equality, proposed teaching black boys some subjects away from their other classmates, after visiting a project in the US for the BBC documentary programme Inside Out.
He suggested that black boys were underperforming because of a lack of self-esteem and positive role models, as well as an attitude that being clever was not cool.
Tony Sewell said Mr Phillips' plan might help to a "certain extent" but that it did not really address the issues.
"It's taking the boys out and doing what with them? In a sense Trevor Phillips has laid himself open to more problems because what we've got with this issue of black under-achievement is too much vagueness."
The main issue was that black boys often felt there was not enough support for them either at school or at home, Dr Sewell added.
Teachers have warned Trevor Phillips' ideas could fall foul of Britain's anti-racism laws.
But a spokesman for the National Black Boys Can Association, which aims to raise the aspirations and achievements of black boys, said it could help.
"It's certainly one of the areas we have actively looked at and can actually see the benefits for black boys within certain subjects being taught in a way that makes the subject more relevant to their particular needs," said the organisation's education advisor, Josef Norford.
"There are certain subjects within the curriculum where black boys do feel more confident if they're away from their peer group."
However, the tactic needed to be used in conjunction with other measures such as mentoring, Mr Norford added.
Trevor Phillips also suggested black fathers not living with their sons should be denied access if they refused to attend parents' evenings.
David Simon of Ebony Saturday schools, which provides supplementary education for black children, said the lack of a positive role model for some black boys was a "valid point".
"But also there are root causes to the disempowerment of black men which he doesn't address. So again it's the blame attitude," he said.
Mr Simon said black boys' problems outside the school environment should be tackled before separating them from their classmates.
"We need to address issues around the learning environment in our homes and the community at large.
"Once we've got that as a foundation we can tackle institutional racism in a much more practical way."
Inside Out will be broadcast at 1930 GMT on Monday on BBC One in the London area.