It seems that today everything is in 3D -- movies, television, console games, and now handheld games. Even though a decent percent of the population gets discomfort after viewing 3D content, technology and entertainment companies are pushing for this new technology to be in every device. Nintendo is no different, but now have actually issued a warning [Japanese] about the damage their new device, the 3DS, could cause.
The warning has been translated by Gizmodo to English, and while the exact translation is rough, the gist is very clear. Children under the age of six should not use the 3D mode on the 3DS as their vision is still developing. This is due to how stereoscopic 3D works, by showing each eye a different image, and actually "has a potential impact on the growth of children's eyes."
Nintendo is not alone on this warning, as Sony also previously had a similar message added to their Terms of Service about their 3D gaming technology for children specifically under the age of six. Sony also warns that children's eyes are still developing and could be damaged by 3D content, including television, movies, and gaming. The company tells parents that if they wish to allow their children to use 3D content that the kids should be checked out by their eye doctor before any play.
Nintendo will have a way for parents to block the harmful 3D content from children by adding in a parental lock on 3D. When activated, the lock will keep all content in a 2D mode. With all of these warnings, and the noted issues that come along with simply viewing 3D content, it does cause one to wonder just how safe the technology is, and if perhaps 3D content should be delivered in a different way.