Some publishing houses are to start "age banding" their children's books later this year.
Each book will carry a specific marking indicating whether they are suitable for readers aged 5+, 7+, 9+, 11+ and 13+/teen.
Research within the book industry suggests people buying books for children would welcome the guidance.
But it is a scheme which has already enraged a number of writers, leading to the creation of a website to protest against the plans.
Here are the opposing arguments.
AGAINST: ANNE FINE, OBE
The branding (for that is what it is) of every children's book with an irremovable age suggestion is an idea that could only spring from people with no knowledge of children and little idea of how a reader is born.
Anne Fine is one of many authors who have expressed concerns
Children read up and read down. They read over and over again. They read the same book at two different ages and get something totally different out of the experience each time.
They identify with characters who are older, and with those who are younger - the reason authors go to such trouble not to pin ages onto their characters.
Children differ. Some race ahead with interests and reading skills. Why should they be held back because, at eight, they want to read something that might be marked 11+? ("Are you sure that's not too old for you, dear?")
Why should the child of eight who struggles with dyslexia, or has English as a second language, or learning difficulties of any sort (and they are legion) struggle to the end of a book and feel their sense of achievement turn to humiliation as they see 5+ on the back?
This is why nearly 1,000 authors and illustrators have already shown their disapproval by signing up to www.notoagebanding.org, and over 2,000 professionally interested people are among the thousands who have also signed up to support them.
These are not stickers. They are clearly printed numbers. Children are taught to study covers. Age guidance is readily available already. This is merely a stupid, cruel idea invented by some marketing maven who thinks only of the convenience of supermarket shelf stackers and nothing of the way in which children come to books.
And it's commercial suicide. If the British publishing industry were looking for the very best way to kill the goose that lays their golden eggs, this would be it.
Anne Fine is a former Children's Laureate (2001-2003), and the author of books such as Jamie and Angus Together, Crummy Mummy and Me, and The Tulip Touch.
FOR: THE PUBLISHERS ASSOCIATION
Each year, more than 9,500 new children's books are published.
The Publishers Association believes the guidance will benefit children
The majority - 55% - are bought by someone other than a parent, usually as a gift. There are some wonderful children's bookshops in the UK where specialist advice on what to buy is readily available.
But just as many children's books are now sold in High Street outlets and in supermarkets. How do we help those adults who aren't familiar with the world of books, and where specialist advice isn't to hand, find the right present?
The Publishers Association's research shows that 86% of adults - both "heavy" and "light" book buyers - said they would welcome age guidance on children's books as one of several tools to help them choose fiction.
HAVE YOUR SAY
Forty per cent even said that age guidance would help them buy more books.
Let children read whatever they want to read
Age guidance, which is open-ended (5+, 7+ etc), will appear in small, discreet type on the back cover of children's fiction, next to the barcode.
It is, along with the cover, illustrations, the "blurb", and design, one of several tools designed to help adults who are unsure what to buy and need extra guidance.
We don't want to miss out on being given a book because the adult doesn’t know where to start. Nor do we want a child to be put off reading for life by a book that they can't cope with.
And we certainly don't want adults to default to buying computer games or DVDs (which, incidentally, all carry age guidance) because they are not sure which book to buy.