Spunky girl books are nothing new. Readers (and other selectors of books) in search of a strong fantasy heroine, an everygirl who know her own mind and isn't afraid to speak it, or a princess who hates tiaras needn't look far. There are also plenty of books and other media projecting the opposite image of femininity. There's nothing inherently wrong with that, but it sure as heck would be wrong if that were the only way fiction portrayed girls. I love me some anti-princess books. But I don't think they're the whole answer.
What about the boys?
We've started to see some books over the past few years about boys with nontraditionally male interests. There's Will Grayson, Will Grayson and My Most Excellent Year and Putting Makeup on the Fat Boy and Better Nate Than Ever. Great books, and I'm very glad to see them being published and succeeding. But these examples have a little too much in common. Three of the four are YA (Better Nate Than Ever is upper-middle-grade), and in all four, the characters who love musicals or makeup are gay or very probably gay.
Again, there's very much a place for these books (though, much as I enjoy reading about musicals, it's a pretty worn-out stereotype). But why must the male equivalent of an anti-princess book always be about sexuality? Apparently, a girl can shoot a basketball or rescue a kingdom without outing herself as a lesbian, so books about girls who break the now-oft-broken mold are appropriate for any age. But it seems that boys who are into the arts must also be into other boys, so books about them become sensitive material, appropriate only for older readers. (There are precious few exceptions among picture books; William's Doll comes to mind, as does The Art Lesson.)
Yes, males have been socially dominant for a very, very long time, and yes, girls have needed role models who break free of established gender roles. But it can't be easy to be a boy, straight or gay or in between or too young to know, who would rather knit or sing than play soccer. We need books that normalize boys with all sorts of interests and personalities, and we need them in sections of the library that boys will visit long before they're reading YA. The world may well be telling them by kindergarten that there's something wrong with them. Let's tell them there's something right.
Edited to add: I just want to make sure it's really, really clear that I'm not saying queerness is a bad thing, or that it's terrible to be "accused" of being queer. I'm just saying that interests are a separate thing from sexuality. Many books about girls seem to understand that, and books about boys need to catch up.