Excuse me if I ramble:)
It seems to me that most parents assume that gender is a hugely important natural category for young children. So take a recent thread about birthday party invites. It is (according to the law of mn) ok to invite all the children in a class or to just invite all the girls or all the boys. But it is not ok to (for example) invite all but one boy and a couple of girls, even if these are the child's actual friends.
I don't intend this to be (another) thread about party invitations, I'm just interested to know whether you think gender is really such and important natural category to most young children that they would notice being (for example) the only boy not to do something? Are the parents imposing the importance of these categories or are they just being sensitive to their children's natural sense of identity?