Boys could pull further ahead of their female peers in the new "tougher" maths GCSE, an expert has suggested.
And the gap between girls and boys could narrow in the reformed English GCSE, according to Professor Alan Smithers.
Professor Smithers, director of the Centre for Education and Employment Research at the University of Buckingham, believes the new maths and English GCSEs could favour boys.
In England, teenagers will receive their results on Thursday for the more demanding maths and English GCSEs – which will be graded from 9 to 1, rather than A* to G.
Last year, boys had a slight lead of 0.5 percentage points over girls at A* to C in maths. Meanwhile, girls were 15.9 percentage points ahead of their male peers in English.
End-of-year exams 'benefit boys'
But Professor Smithers thinks the downgrading of coursework and a shift towards end-of-year exams could benefit boys.
He said: "In maths, girls were once ahead, but were overtaken by the boys in 2009, since when boys have maintained a narrow lead.
"The more demanding content and end-of-course examination should see that gap widen."
Professor Smithers added: "Girls regularly have been massively ahead in English at A*-C by between 13 and 16 percentage points.
"It is likely that the switch to 80 per cent end-of-course examination will dent this lead."
And his prediction came true. Boys actually received more A* and A grades at A level than their female peers.