Yeah, I know a set of parents that we’re doing the same thing for their daughter. Kept rejecting guys because they didn’t feel he was up to par. The guys info wouldn’t even make it to get to accept/reject.
Their daughter is now 40 and unmarried. They rejected so many guys that people just stopped approaching her.
It absolutely leads to sin unless you are a fantastic mu'min. And yes, although they might not turn to haram in terms of having relationships with girls, but you can't tell me you didn't see these guys talk about some girls in lustful ways or look at them in such a way.
Furthermore, and something we seem to forget, is that in these gender mixed schools there is gender mixing in everything. In sport, as an example.
Boys turn to watching filthy films whether they are in segregated or gender mixed schools.
No brother. What I do is this: I pray 17 rakaat Qadha prays everyday plus 11 rakaats Salaat-ul-layl. Salaat-ul-layl is something that does NOT have any replacement. It gives you good feeling. It really gives human being feeling of being in heaven.
If you do Salaat-ul-layl, keep going. It guarantees both Dunya and Akherah.
I can give my opinion on men, as I'm not sure about women.
I might have a pretty biased view due to personal experience, but some guys can get pretty desperate if they are segregated.
Also how does co-ed lead to sin? Most guys who were my friend in high school turned to pornography to sin, rather than girls. We might as well provide them with home schooling in that case.
Trust me, we need to teach guys to respect women in this day and age. Alienating women is not the best option.
To be fair, there is a disadvantage of co-ed. If parents don't monitor their children, then there is a risk of them getting into the boyfriend/girlfriend culture.