A group of MPs have said that ministers should rethink when children born late in the academic year are put into school.
The House of Commons Education Select Committee has said authorities and academy schools should offer flexibility to youngsters born in the summer.
They are often put straight into year one which means they miss out on the reception year and vital learning.
There are also concerns that this leads to children being behind in what they know and also opens them up to bullying.
Committee chairman Graham Stuart said: “Our recent evidence check examined issues related to school starting age. It was very clear that the month of a child’s birth has a measurable effect on their academic outcomes and their likelihood of SEN (special educational needs) diagnosis.
“We also heard that there is a greater risk of summer-born children being bullied, and placed in low-ability groups.
“In particular, some parents find their summer-born child may be forced to start school in year 1, rather than reception, when the child reaches compulsory school age. Even if parents think their child is not ready, they currently have no right to appeal this decision.”
Current guidance requires school admission authorities to provide admission in the September following their fourth birthday.
However, there are compromises for parents who feel their child is ready to begin school before their compulsory school age.
The committee called on the Department for Education to undertake an analysis of which admission authorities are observing the guidance, and to consider the merits of using a child’s due date rather than birthdate in admissions policies.