Exposure to electronic media can, when used correctly, enhance children's development. For children that are two and over, if used properly with the right software or applications and with direct parental involvement, there can be some positive benefits.
It's really felt that children learn best by hands-on, real life experiences rather than the sort of second hand experience from an electronic device. Especially for children less than 15 months of age, it was found that they have a hard time transferring that information that they may see on a screen to a three dimensional real world type of setting.
The message I want to give is that for children especially less than five who are using electronic media, this should not be a passive experience. There should be a direct parent involvement to use as an educational tool.