Children born in the summer months should have lower pass marks than their older classmates, according to a new report.
The Institute for Fiscal Studies (IFS) calls for GCSEs and primary school tests to be "age-adjusted" to ensure "that those born at the end of the academic year are not disadvantaged by taking the tests younger".
Children born in August are 6.4 percentage points less likely to achieve at least five Cs at GCSE, according to the IFS.
Pupils are also two percentage points less likely to go to university when they leave school.
The publication of the report comes amidst growing concern that children born at the end of the academic year achieve less than older classmates.
The IFS is calling on ministers to take action to deal with the effects of the differences.
Ellen Greaves, research economist at the IFS and one of the report authors, said: "Age-adjusting the cut-offs required for pupils to achieve particular grades would ensure that no child is prevented from going on to further or higher education simply because of the month in which they were born."