He has a much healthier relationship with the opposite sex than I ever had because of it - I went to a single sex school and had little chance to interact with boys.
Yes, I totally agree encouraging girls and boys to mix is important.
I went to a girls school, and then a mixed school, and the attitude of girls towards boys was much healthier at the mixed school.
But that's not the same thing as where you choose they sleep.
Honestly the wilful naivety on this issue is shocking. And it's teenage girls who will suffer, because it's them who will have to deal with unwanted pregnancy.
Saying you provide condoms as a solution to the risk of teen pregnancy just shows you don't understand teenagers. Yes, having condoms available is a good harm minimisation strategy, but a much better one is not letting them sleep together in the first place.
Instead of you being the adult and protecting these young girls, you're saying the responsibility for them not getting pregnant lies with them. You expect a young teenager to stop unplanned sex in the middle of the night, to go wake up an adult and ask for condoms? Seriously? That's your plan for preventing teen pregnancy?
You are failing those girls.