Nintendo has released a 'warning' webpage about the 3DS. They suggest that people should take breaks while playing the 3DS - half hourly breaks are recommended because of the 3D display. Nintendo also warns that children that are aged six years or younger should avoid the 3DS altogether. According to Nintendo, while the vision is still developing in these ages it is not recommended to play 3D games or watch 3D movies.
The 3DS includes a slider that lets you choose the depth of field, and you can set it al the way to 2D - so young people can play it after all. Parents can also 'lock' the 3D mode if they want.
