The growing number of toy-themed virtual worlds aimed at young people risks undermining the basic human values we wish to instil in children.
Many children are keen computer gamers
So said industry veteran Lord Puttnam opening a London conference devoted to discussing virtual worlds.
He feared that all children will learn from these virtual spaces is that they are first and foremost consumers.
He urged creators to build more moral virtual worlds that instil in children the values that societies need.
Oscar-winning film-maker Lord Puttnam gave the opening keynote speech at the Virtual Worlds Forum held in London from 23-26 October.
In his speech Lord Puttnam voiced fears about the many game worlds that have sprung up which tie access to the virtual world to the purchase of a toy.
Webkinz, Funkeys, BarbieGirls, TyGirlz and many others are all virtual worlds created and run by toy makers.
"Are we absolutely sure that this is the very best we can offer young people?" he asked. "Do we really want them to think of themselves as not much more than consumers?"
He said: "Might we not prefer to build worlds that encourage those same values and skills we wish them to exercise in the real world?"
"The challenge ahead is this - to ensure that virtual worlds are increasingly places that offer real meaning to their lives and in the real world to learn from the sense of community and collaboration that's been experienced in virtual worlds," he said.
Those involved in creating virtual worlds for children got their chance to answer his criticisms during a panel session at the conference.
Many toys now have their own virtual world too
Matthias Mikshe, founder and head of Stardoll, said many firms were developing virtual worlds for children because young people were far more familiar with them than their parents.
"This is the first digital generation and for them this is just natural," he said. "It's our generation that calls it a virtual world and builds some mystique about it."
Alice Taylor, commissioning editor for education at Channel 4, said: "It's people of a certain age that talk about 'going online'. Kids just say 'I'm going to Habbo'."
Marc Goodchild, head of interactive and on-demand at BBC Children's, said virtual worlds for children were popular with parents too.
"The social footprint of kids is diminishing year on year," he said, "they are allowed less distance from the front gate all the time."
Virtual worlds, he said, let them play with their existing friends and have some of those shared experiences they would otherwise miss.
Specifically answering Lord Puttnam's point Mark Hansen, director of business development for Lego Universe, said children were very good at determining the underlying ethic of a virtual world.
"Is it positioned to sell more product or as an extended experience with the product they have already bought?" he asked. "Kids are very smart and will spot that really quickly."