People seem very bad at recognising cultural programming, friends tell me their 3 year old boy just prefers train sets and their girl prefers to pretend to cook without recognising the millions of cultural signals they've received by that point. Actually cooking is another good example - look at the top chefs and how male skewed they are. A lot of it is about telling boys it's ok to be aggressive and acquisitive while telling girls it's better to stay in the background and adopt a supporting role.
[1] http://muse.jhu.edu/login?auth=0&type=summary&url=/journals/...