A-levels exam genes
Choosing to do A levels and performance in exams may partly depend on our genes. Christopher Furlong/Getty

Whether people choose to study A levels and the topics they select are more strongly influenced by genetic factors than environmental ones, scientists have said. Furthermore, performance after two years studying the subjects also appears to be linked to DNA.

To investigate the extent to which genes play a part in education outcomes, the study, published in Scientific Reports, looked at how twins fared in the educational system when between the ages of 16 and 18 – a time when education stops being compulsory in the UK.

Many studies have shown that academic performance and general intelligence can be heritable.

But up to now, it wasn't clear if that was also the case for the decision to pursue non-compulsory education.

Here, the scientists discovered that both environmental factors account for important differences in academic choices.

Twin analysis

The researchers examined academic data of 6,584 pairs of twins who took part in the Twins Early Development Study. Comparison between the twins and between each pairs of twins allowed them to assess the genetic contribution in choosing to do A levels and subject choices at the age of 16, as well as achievement in the chosen subjects when aged 18.

Environmental factors were also taken into account, such as school and family influences and parental advice for choosing to do A levels.

While the decision to choose to do A levels appeared only moderately associated to genetic factors (influencing 44% of the decision), subject choice was much more influenced by parents (50–80%) and less influenced by the environment.

Similarly, A level mean performance was highly dependent on parental factors (59%) with only a small proportion of the variance explained by environmental factors (7%).

How DNA affects choices

This is the first time that a study shows that genetic factors not only influence achievement, but that they also drive academic choice. In a second part to the study, the researchers tried to explain the mechanisms behind this.

The first hypothesis is that students choose their subjects based on previous achievements, which are themselves highly dependent on parents. The second one is that the decision to keep on with A levels and to choose a particular subject is also linked to people's general intelligence - there again very heritable.

Future research could focus on whether a specific DNA sequence is associated with academic choice and achievement, but the scientists believe it is more likely that thousands of DNA differences – each of very small effect size – are responsible for how we make educational decisions and how we perform in school.