When children stop mixing with opposite sex

[MillyTheKid]

I don't mean at school and outside the house but I find it a bit sad when it's suddenly all computer games mad boys coming round to the house and invited to birthday parties rather than the mixed crowd it used to be. I guess it's all part of growing up.

They don't, necessarily.
All of us tend to prefer to spend time with people who have similar interests though.

I'm not sure they do.

Maybe he's just going through a boring game boy phase.