Yes, it's sexual discrimination the same way that many "faith" schools are able to discriminate based on the religions of the parents of children.
It does seem religion has this privilege, even in the UK's relatively secular and free society.
From this point I got a thinking about a tangent. Would it be fair to say that most faith schools perform better than non religious schools? I don't know the stats on it but presume that is the case as I hear of a lot of lay Catholics following the protocol of masses every Sunday and feigning Catholicism just so they can get their kids into Catholic Primary School. My sister in fact did this. But anyway, back to the point and that is why do faith schools perform better if they indeed do?
Does religion bring better familial discipline and therefore better behaved children? Sort of confused by it.
Out of all the schools, in the area I live, the pupils of the faith schools are far better behaved, look less scruffy and are more polite. This is purely my own observation and not backed up by statistics or a criminal register of sorts.
Similarly purely on an anecdotal basis I did teacher training in 2 state schools in Derbyshire
The catholic state school had a solid culture of learning and respect and the school priest was basically the school counsellor in charge of the pastoral welfare of the pupils
The bog standard comprehensive was staffed by teachers who just wanted the easiest way of controlling the herd and achieving vaguely respectable league positions to secure funding; pastoral care was dealt with in the least disruptive (to the staff) way possible.
My impression from talking to people in other schools was that the better schools were down to better staff rather than any difference in pupil intake - maybe the in-demand faith schools get that way because of the virtuous circle of: better staff - better pupils - better results - better staff
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