A report commissioned by the School Curriculum and Assessment Authority says that pupils taking science subjects score lower grades than those of equal ability studying the arts.
After physics and chemistry the most difficult subjects were mathematics and biology, but foreign languages and general studies were not far behind.
The study raises the possibility that A-level syllabuses in these subjects might have to be made easier so they equate with others. But the exam boards say the differences are intrinsic to the subjects and are not their fault. They believe the same problem would be found if degree level courses were examined.
On average, physics candidates could be expected to gain one grade higher in biology or computer studies, but if they took environmental studies, psychology or accounting the difference was two grades.
The researchers say that the more academic pupils have probably tended to opt for science subjects in the past, and that examiners in this area have become used to dealing with the higher ability bands. The notion that poor maths and science teachers may be causing their pupils to do badly is allayed by international comparisons which show British pupils to be second only to Hong Kong in maths and science ability, they say.
A spokeswoman for the assessment authority said it was consulting on the findings. The universities' admissions service was being asked whether concessions were routinely made for scientists and research was monitoring the effect over time. However, there was a possibility that some syllabuses might have to be made easier and discussions were taking place with examination boards, she added.Reuse content