A Japanese ophthalmologist warns of the possibility of severe damage to the eyes of young children should they use the 3DS.
The doctor's warning:
http://www.sankakucomplex.com/2011/02/07/doctor-3ds-makes-children-cross-eyed/3D images are bad for the eyes of infants. Nintendo says as much, and for children not to use it. The reason is that there is the possibility of damaging the eye’s balance and inducing squinting/strabismus.