The Association of Teachers and Lecturers (ATL) has heard that proposed changes to the way GCSEs are examined may hinder secondary teachers' efforts to continue improving female pupils' grades.
Earlier this year, education secretary Michael Gove confirmed plans for GCSE exams to be taken after two years instead of in a series of smaller units, as well as for less emphasis to be placed upon internal assessments, including coursework.
Data indicates that over the past 20 years female pupils have outperformed their male counterparts at GCSE level; last summer, 73.3 per cent of GCSEs taken by girls received at least a C grade, compared to 65.4 per cent of those taken by boys.
Yet speaking at the ATL's annual conference in Liverpool, former chief examiner in chemistry and retired teacher Geoff Venn warned that the planned changes to the GCSE could hinder female pupils' recent progress.
He asserted that girls tended to be less confident going into high-stakes tests than boys and that, when GCSEs were first introduced in the early 1990s and female pupils started to perform better, especially in science subjects, it was felt this was due to the new forms of assessment being used.
Mr Venn argued: "If we go back to pure rote learning, to pure single exam at the end of the course, will this have a considerable gender impact on the results that we get? Is it going to be discriminatory against girls?
"I have a strong feeling that it will be. I think it's one of the aspects that needs to be looked at before we go forward with this type of assessment and examination."
ATL general secretary Dr Mary Bousted concurred that girls' improving performance at GCSE could be down to the "more measured" assessment methods introduced since the introduction of the GCSE, of which coursework was a part.
However, a DFE spokeswoman rejected these suggestions, telling BBC News that there was no evidence girls did more poorly on final year exams.
She contended instead that education of male and female pupils alike was hindered by over-reliance on modules, coursework and controlled assessment, claiming that these were subject to "gaming" and took time away from teaching and learning.
Posted by Harriet McGowan