Here's a discussion I've been meaning to write for a while, requested by commenters. A few years ago, I read a Horn Book article about the lack of mothers in fairy tales and books, and it mentioned, among others, Princess Academy. The article's writer (I'm embarrassed I can't remember who) challenged herself to change that and write a book where the protagonist's mother was a present, strong character. She talked about her work and how she had to scrap it. In a story, it's just impossible for a child/teen to have any adventures, to grow on his/her own with a mother present. The mother would take care of everything, the mother would carry the burden of worry. You want your protagonist to be as close to and involved in the action as possible, and for a young protagonist, a mother (a capable, present mother) will interfere.
I tried the same thing once. I was determined to have a mother and father who were present, who had the adventures alongside my hero. Again, it didn't work. Boring. The real growing up a person does is gradual and often subtle. In a story, you speed things up, let a few large events stand in for a hundreds of small events. If a mother especially is there, the young character doesn't have a chance to grow, to make choices, to be a hero.
So why not make the mother herself the character? Traditionally a children's book has a child as the main character. I can think of only one exception: the extremely wonderful Mrs. Frisby and the Rats of NIMH, and it's subsequent movie, The Secret of NIMH (notice the title change--no need to highlight a Mrs is the main character, after all). Any other mother main characters I'm missing?
While this is a general rule, great authors can break it. I can think of many wonderful mother supporting characters who manage to stay out of the protagonist's way.
Charlotte, that lovely spider. What a clever device! She's a mother character, and yet she's so small and vulnerable with such a short life span. She can't take care of everything, but just enough.
Mrs. Weasley is great, one of the most memorable mothers in literature and film. If she'd been onsite, she would have prevented some adventures. Rowling got around that with the boarding school scenario.
I think of Elastigirl from the Incredibles, but the children are not the main characters, and she does have to leave them alone at one point--the point at which they really come into their own powers.
Looking over my own books, about half the mothers are dead. Jack, Rapunzel, Rin, and Razo have excellent mothers who aren't perfect but definitely have strengths. They all must leave them behind to have their adventures or save their mothers themselves.
What do you think about the missing moms? Any examples of present mothers who didn't get in the way? What about fathers?