SIngle-Sex Schools!!!?

I'm doing a debate and I am AGAINST single-sex schools. I'm almost positive that the opposing team (who supports single-sex schools) is going to say that girls gain confidence at single-sex schools. I wanna say that they'll lose confidence when they're adults, but can't find any evidence!!! PLEASE send some evidence saying that they'll loose their confidence when they're adults because they'll need to deal with the opposite gender. Thanks, that would be sooo helpful!

SIngle-Sex Schools!!!?
This is what I can come up with. The girls can lose confidence as they become older is because females are very critical of other females. Whatever their peers have drilled into them about being unattractive, overweight or underweight and everything else. They also wouldn't have a lot of experience in associating themselves with males due to the fact that they weren't able to be around them on a daily basis while in school. Hope this helps some.
Reply:I went to an all girls school - got to be honest, it was fantastic lol, I did gain a lot of confidence - but as I got older I realised that all my friends who had grown up around boys at school were better able to 'read' the boys and so are more natural and confident around them :-)