I went to mixed sex comprehensive schools. My parents could have afforded to send either me or my brother to private school, but not both of us, so they decided it was fairer to send neither of us.
When I was in year 6 my teacher tried to encourage my parents to enter me for scholarships to nearby private schools. They decided not to.
One of the reasons they decided not to was because I did much better at school than my brother, and so they were worried that if I got a scholarship to private school but then two years later he didn't, we would have been treated unequally.
The other reason was that all the private schools nearby were single sex, and my dad in particular thought that I would become a better rounded person if I went to a mixed sex school.
At my first secondary school I was horribly bullied. Mainly by girls, it has to be said, but the boys were not particularly nice to me either. And my learning was affected, not just by the bullying but by extremely disruptive and badly behaved boys.
At my next secondary school, I was much happier, but there were still quite a lot of disruptive boys. This was a particular problem in science, because the school did not have many decent science teachers and none of them could cope with bottom sets, so we were taught in completely mixed ability groups right through to GCSE. In year 10 my one experience of dissection was brought to an abrupt halt by the boys deciding to throw pigs' kidneys around the classroom until the teacher ran away in tears.
I still got very good GCSEs at that school, by most people's standards. I got A stars in the arts and humanities subjects, As in maths and science and a couple of Bs. Because I considered maths and science to be my weaker subjects, and being a girl, was never really pushed in the direction of STEM subjects, I dropped those subjects immediately after GCSE, which severely limited my further education and career options later.
I can't help but feel that if I'd gone to a super academic girls' private school I would have been equally pushed and challenged in all my subjects and would probably have got straight A stars across the board. I didn't really socialise with boys anyway, so I'm not sure whether having them in my classes really made all that much difference to my social skills. I went to 6th form and university with plenty of girls who had been at single sex schools until 16 or even 18 and I simply don't recognise this stereotype of girls who have had a single sex education going off the rails as soon as there are boys in the vicinity. I think that's a myth.
If I had an 11 year old daughter today and I had the opportunity to send her to a single sex secondary school, I think I would. For all the reasons mentioned above, but also because teenage boys these days are so porn addled and all have smartphones in their pockets and I have no idea how we are supposed to given our teenage daughters the skills to cope with all of that when they're at school and supposed to be learning.