To redress the balance, August-born children could spend a year longer at school under proposals put forward by the study’s authors.
Ministers are expected to back their idea to overhaul tests so pupils sit exams when they are ready rather than at fixed points through school.
The shake-up would involve ending the arbitrary system which expects pupils to reach academic levels by the end of a “key stage” at school.
They would instead be expected to achieve those levels by a certain age, for example the crucial “level four” by eleven-and-a-half rather than by the time they leave primary school.
Researchers from the Institute for Fiscal Studies said children should still move through school with their usual age group, but teachers should allow them flexibility to take tests later than autumn-born classmates.
It could result in those who struggle to overcome the setback of being born in summer spending up to a year longer at school.
Study co-author Claire Crawford said children face a penalty “simply because they are unlucky enough to have been born late in the school year”.
Ministers called the report “very interesting” and said they are considering its proposals for inclusion in a flagship Children’s Plan due later in the year.