Children differ widely in how well they do at school. In recent years, researchers have shown that around two-thirds of differences in school achievement can be explained by differences in children’s genes.

Genes have been shown to influence how well children do at primary school, at the end of compulsory education, and even in different subjects.

But less is known about how genetic and environmental factors contribute to how well a child continues to do academically throughout their time at school.

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To study this, we used a sample of more than 6,000 pairs of twins who are part of the UK-representative Twins Early Development Study and analysed their test scores from primary school to the end of compulsory education. Our new research found that the twins’ educational achievement was remarkably stable: children who do well in primary school also tend to perform well in GCSE exams, which are taken at the end of compulsory education.