As another poster said, it’s because they are emotionally and socially immature compared to the children who are older, yet they are expected to show the same behavioural traits and skills that the older children do. When the summer borns are unable to do this because developmentally they aren’t at that stage, their behaviour is questioned as being due to SEN as opposed to simply understanding that they are too young to behave like the others.
For example, me and my friend both had Summer Born children, born within two days of each other, and she sent hers to school just after he turned 4 whilst I deferred mine.
In Year 1 the teacher raised concerns about my friend’s son’s inability to stay focused on the academic learning and getting distracted comapred to his classmates, and by the second half of Year 2 he had been referred for SEN assessment. He’s now in Year 3.
My son is almost identical in behaviour to my friend’s son, they act exactly the same age (because they are) but her son is query SEN whereas mine isn’t. My friend’s son is being compared to the other children in his Year 3 class and his behaviours and academic abilities are deemed to be below the expected levels (for want of a better word), whereas my son is being compared to his Year 2 classmate and he is deemed to be perfectly fine.
I’m definitely not saying it’s that black and white, but it’s just an example of how summer borns can be labelled as being low achievers, or displaying disruptive/problematic behaviour, when actually they’re are fine but they are just being compared to other children who are in some cases much older than them and are more developed in their social and learning skills.
Her son is now being taught one-to-one in some lessons (maths and English) as his inability to focus like his peers has meant he has fallen behind them over the years. On his report he is classed as “achieving below expected standards” even though his reading and maths ability are exactly the same as my deferred son who is classed as ‘achieving at expected standards.”
My friend isn’t pursuing the SEN path for her son as she doesn’t see anything in his behaviour at home that warrants a diagnosis (nor do I and I spend a lot of time with them). She really wishes she’d deferred her son a year as she thinks all of this would have been avoided.