Results published yesterday showed boys outperformed girls in mathematics for the first time in more than a decade after being awarded more A* to C grades.
The move followed the abolition of maths coursework – which traditionally favours girls – two years ago.
Ministers have announced similar plans in other subjects, with coursework being scrapped amid fears pupils are copying from the internet or asking parents for too much help.
It will be replaced by a system of “controlled assessment” – longer projects and essays completed under teachers’ strict supervision.
Heads said that the move – being introduced from September – would herald the end of the 20-year gender divide in examination results.
John Dunford, general secretary of the Association of School and College Leaders, said: “Boys have overtaken girls at GCSE maths. It clearly shows how the type of assessment directly affects achievement.”
He added: “I think we will see a situation over the next couple of years where boys will catch up with girls as a result of this change.”
Almost 750,000 schoolchildren in England, Wales and Northern Ireland received GCSE results on Thursday.
Some 21.6 per cent of exams were graded A* or A – the 21st year-on-year rise since GCSEs were introduced in 1988.
Girls continued to outperform boys overall. Some 70.5 per cent of girls’ papers gained at least a C – considered a good pass – compared with 63.6 per cent of boys, but it was the smallest gap since 1991.
In maths, boys reversed the trend as 15.5 per cent of exams gained an A* or A, against 15.2 per cent of girls. They also dominated B and C grades.
Dr Mike Cresswell, head of the Assessment and Qualifications Alliance, Britain’s biggest exam board, said: "The obvious speculation is it reflects the removal of coursework from GCSE maths. It's well established that girls outperform boys at coursework."
Girls, seen as more conscientious, usually gain better marks in coursework as they work harder over a longer period.
But record results published by the Joint Council for Qualifications masked serious concerns.
The number of good grades awarded in English fell for the first time in more than 10 years, prompting fears that state schools were struggling to prioritise the subject in the face of increasingly crowded timetables.
Fewer pupils were also entered for GCSEs in languages. French and German entries have almost halved in just seven years.
Independent schools also stretched their lead over comprehensives. A grades increased at around three time the rate seen in the state system. It comes despite the fact that around half of leading private schools are now axing GCSEs in favour of the International GCSE, which is modelled on the old O-level.
A poll for the BBC’s Newsnight last night found 67 per cent of people believed Labour had failed to deliver on education since 1997. Some 63 per cent said investment could have been better used and only a quarter believed Labour had the best education policies.
But Vernon Coaker, the Schools Minister, said: “I’m really pleased to see that this year’s GCSE results show sustained progress in standards. Good results are the product of students’ hard work and excellent teaching in the system.
“The improvements in maths grades are particularly welcome and reflect our sustained focus on getting the basics right. However, it is disappointing to see a slight fall in the English A* to C rate. We are not complacent and are targeting our efforts on ensuring that every child performs to their full potential.”
But Nick Gibb, the Conservative shadow schools minister, said: “It is a cause for concern that the inequality gap appears to have widened dramatically this year, with independent schools increasing their haul of top grades at almost three times the rate of comprehensives.
“We now have nearly half of all independent schools abandoning the Government’s maths exam in favour of the iGCSE qualification, which is effectively banned from state schools because it is not included in league tables. This means that the majority of pupils are unable to compete on a level playing field with their wealthier counterparts.” By Graeme Paton, Education Editor Published: 10:30PM BST 27 Aug 2009