I'm not a mom and not planning to be, so for me, this lack of representation isn't as visceral. But it's still really noticeablee! I'm looking at my shelves now, and there are none where a mother is a major protagonist or viewpoint character.

Actually, the only one I can really think of is ... Cersei ... and she's an antagonist in a story with a very large cast.

But, you know - there are stories there. A lot of fantasy and sci-fi erases or minimizes a character's familial relationships: The protagonist moves sets off on the journey alone, perhaps meeting new people along the way - but leaving the old ones behind. Maybe their family was awful, or maybe their family was killed; it all gets the family out of the way so the "story" can happen.

(To be clear, I don't think that's the only issue - dads are also underrepresented in genre fiction but not nearly so much.)

Trying to write a story in which these kinds of relationships are present and an important part of the characterization could result in a really good, and really DIFFERENT type of story. I'd be interested to see more of it, especially outside of... what might I call it? "Dynastic" fantasy? I'd like to see a mother and daughter whose relationship isn't important because it's part of a political plot, but because they're family.