You definitely can't separate out your own biases easily, but that's not to say there are no sex differences. Here's an interesting article on the gender toy preferences of monkeys:

http://www.dailymail.co.uk/news/article-1196183/Why-boys-pic...

I try to accept these differences and go with them as a parent, not ignore them or spend my time blaming society. I don't think they are incompatible with the hopes and dreams I have for my daughter. I don't think a preference for dolls means my daughter has to be a waitress instead of an engineer.