I have a daughter. I want her to know that she is every bit as good and able as a boy to do whatever the hell she wants in life. So many girls' t-shirts, dresses, toys say things like "princess". Princess isn't much of a job. It basically means sitting there waving at people while wearing a pretty dress. Meanwhile, boys' clothes say stuff like "pirate" or "pilot". I tell my little girl she can be an engineer, a ninja, a psychologist, a doctor, a zookeeper, an artist, an international jewel-thief, an astronaut....whatever she wants really.
Even if she wants to be a princess, fair enough. But she's not going to have it thrust upon her. She's clever, she's beautiful, she can be anything she wants to be.