You can't just put them all in trousers and pretent they're the same, for God's sake, we make boys and girls use different toilets at school, they KNOW they are different, the know by the time they are five that 75% of girls in the class are confident readers and 75% of boys in the class aren't, they know that in any group of fifty girls and fifty boys, if someone flicks mashed potato it was probably a boy, and if someone cries because it landed on them it was probably a girl (and I see her damn point, it's not nice eating with small boys!)
This is prejudice, it's observation. Like it or not, for whatever reason, they are different by the time they go to school.
If they just had two top children, they would always be girls. AQlways. Girls behave better, listen better, play nicer, sit stiller, write neater, read faster, you only have to sit in a year 1 classroom for 3 hours to see this is the case. They HAVE to make sure a boy gets a prize or the boys will cop on that in the real world they have no frigging chance until they hit puberty and their brains catch up. And that might be too late to recapture there enthusiasm for school - they will have learned that school is for girls. It's what girls do.