The Wellcome Trust comments on 2013 GCSE examination results

Today secondary school students across England, Wales and Northern Ireland received their GCSE results, revealing continued growth in numbers taking separate physics, chemistry and biology subjects - showing increases of 2.1 per cent, 4.4 per cent and 5.0 per cent, respectively.

Grades have fallen for the second year running, and there has been a significant decrease in the number of students attaining A*-A grades and a smaller fall at C grade. This reflects a toughening up of exam standards in science, which is welcomed by the Wellcome Trust.

However, the Wellcome Trust has warned that new accountability systems for English schools risk undermining the balance of science subjects taken at GCSE level. Evidence from Northern Ireland suggests that this may result in a fall in the number of students taking all the science subjects and increasing gender divides; for example, reducing the numbers studying physics, especially among girls.

Over the past five years, students in Northern Ireland have no longer been required to study a balance of all three science subjects (biology, chemistry and physics) at GCSE level and can choose instead to take one, two or three qualifications in these subjects individually. This has led to a striking change in the distribution of science subjects studied.

Under changes to assessment and accountability in England, there are concerns that pupils at state-maintained schools may no longer take a balance of all three science subjects, whether as individual GCSEs or as a balanced double-science exam, and that this might lead to similar changes in the distribution of science studied.

Sir John Holman, Senior Adviser in Education at the Wellcome Trust, said: "We are very pleased to see the continuing growth in the popularity of the sciences in general, but Northern Ireland has a warning for England. With the forthcoming changes to secondary school accountability in England, we may find that schools move away from the norm of entering all pupils for courses that are balanced across physics, chemistry and biology. This could result in gaps across the breadth of scientific study."

In 2007, entries for biology, physics and chemistry GCSEs in Northern Ireland were spread evenly across the subjects and genders. But in 2013, this has changed: 4489 pupils sat biology, 54 per cent of whom were female; 3195 sat chemistry, 49 per cent of whom were female; and 3092 sat physics, 41 per cent of whom were female.

Sir John added: "It is important that pupils have a balanced science course to age 16: physics, chemistry and biology are equally important for scientific literacy. Ministers in England need to make it crystal clear that, whatever the complexities of the new accountability system, all pupils will be expected to follow a science course that includes elements of the three major sciences to the age of 16."

Today's results follow the announcement last week of A-level results, which showed continued growth in the number of students taking sciences at A level.