That the American Girl dolls only have violins, the piano, the guitar, and the flute as available instruments for your dolls.
I thought they were to empower young girls, not to enforce stereotypes. Strings, woodwinds, and the piano may be popular and 'girly' instruments, but come ON, my friend Rachel is first chair trombone and she can play with more volume and musicale than the other five boys in her section.
Not to mention I'm first chair French Horn (still elegant but unappreciated, also I like to brag.)