The Gruffalo and Winnie the Pooh may be bad for children's learning, according to a, (frankly, ridiculous) report from psychologists in Canada.
The study suggests because animals do not talk or wear human clothes in real life leads under-fives to think animals are like that in real life.
They'll be telling us the Easter Bunny doesn't exist next!
Researchers from Toronto University's Department of Applied Psychology and Human Development said children need to read more factual books about the natural world.
They conducted tests on children aged between three and five by reading factual animal books to some and literature giving animals human characteristics - known as anthropomorphism - to others.
They were then tested on their knowledge of wildlife and those who had heard stories about talking animals were more likely to think real animals could talk, the psychologists said.
Professor Patricia Ganea said: "Books that portray animals realistically lead to more learning and more accurate biological understanding.
"We were surprised to find that even the older children in our study were sensitive to the anthropocentric portrayals of animals in the books and attributed more human characteristics to animals after being exposed to realistic books."
The report, in the journal Frontiers in Psychology, said: "(We) advise parents and teachers to consider using a variety of informational and nonfiction books, and to use factual language when describing the biological world to young children.
"Children's books that feature talking animals, or animals displaying other human characteristics, like wearing clothes, lead to less realistic understandings of the natural world.
"Such books not only inhibit specific, factual learning but also interfere with children's abstract thinking and conceptual reasoning about animals."
Mercifully, the professor doesn't want parents to stop one of the most enjoyable things about being a mum or dad – reading our kids bedtime stories.
She said we should add books with more realistic interpretations of animals as well.
Like The Tiger Who Came To Tea, perhaps? Or my youngest's current favourite, Cows In Action?
What about fostering children's imaginations?