I grew up able to shrug off a lot of gender preconditioning when I hit adolescence and then adulthood. There are no boy chores and girl chores. There are still girl clothes that are not boy clothes, but not a whole lot of boy clothes that are not girl clothes, but that's a societal thing. (It bothers me that some of my co-workers are fundamentally bothered by the thought of Spongebob's dumb friend the starfish wearing fishnet stockings.)
Hard and fast "girls don't" and "boys don't" rules bother me. As a general rule, the only "girls don't" and "boys don't" that I care to take seriously involve the original equipment manufacturer anatomy, except that people who are strongly mentally gendered who are born into a body with the wrong plumbing totally turn those things upside down.
Statistically speaking, there are always people on the fringes. If you set the scope too narrow and hard, no one fits and everyone hurts. If you set it too wide and fuzzy, there are no differences, and the wonderful rainbow of possibility is greyed out in a muddy blur. Best to make generalizations. "Many girls." "Many boys."
