I think the point is that theres nothing wrong with kids preferring or doing or being anything, it's just the label that's the problem, because that starts to define a whole lot of other things too... No one knew how to define baby X, so baby X could prefer and do and be anything without others thinking that if X liked this then X should like that too, or if X was this then X shouldn't do that...

I like it

Oh and yes, a lot of the time when I'm at work girls prefer the traditonally 'girly' toys and boys prefer the transitonally 'boyish' toys. But you can't say thats genetic. They do go home and receive influences which could very well be that boys play with this sort of toy and girls play with that sort of toy.