Do you know this scenario?
You have a student who struggles a bit as a reader. When she heads to the classroom library, she picks the longest book that she can find. When you try to steer her towards something a little less daunting, she insists that THIS is the book that she wants to read.
What about this scenario?
You have a student who is a proficient grade level reader. Mom and dad are very proud and want to continue to “challenge” this reader so they take him to the bookstore and find the thickest book in the children’s department, buy it, send him off to school, and insist that this is the reading that this child not only wants to be doing but SHOULD be doing.
While these scenarios are different, they have a thread of similarity running through them: they share the notion that good reading is synonymous with book length.
When I think about how this notion was born, I realize it’s pretty transparent. As emergent and early readers, we look at our reading role models (parents, teachers, older siblings). We notice that their reading is infinitely longer than the Dick and Jane books that we are reading. It seems like those readers, the ones we want to be like, are toting around much bigger books—they are longer, they are thicker, they have more words, the print is tinier. Those readers are way better than us, so therefore, when we are able to read stuff that looks like that, that must mean we, too, are good readers.
In the same way that good spellers almost automatically earn the title of good writer, people carrying around long, thick books earn the title of good reader, regardless of whether it’s deserved. What the girl who struggles in the first scenario and the parent who insists on the long text in the second scenario are failing to realize, however, is that good readers choose books for many reasons, and length is but one factor. Who Moved My Cheese 
It's very sad to me that thick books are becoming almost trophies to some parents, proof that their little darling is smart. I worry that this sort of parenting will contribute to a culture of non book reading, because thick does not equal enjoyable necessarily.
You are so right! It seems that whenever I talk to teachers the issue of parent re-education comes up. There are a lot of misconceptions floating around out there that I think we need to debunk. Some parents cover the pictures when children read and make them focus on the words. They overemphasize sound it out. They drill their kids with word flashcards. They are all well intended but I fear the same thing you do: creating a culture of non-book reading. I've been incubating a book on this topic and have the proposal written…I think you've just given me the incentive to get it out there!
Good for you, Kim!