Writing in the Archives Of Disease In Childhood, Dr Sigman said such extensive use of televisions and tablets could also lead to attention problems and other psychological difficulties.
The amount of time spent in front of a screen could also adversely affect children's social relationships.
He said many parents use the devices as "electronic babysitters" as a means to occupy their children.
"Screen time appears to have created the three-parent family," he added.
More top news
According to the poll, conducted for The Irish Times, the country chose to liberalise its laws by 68% to 32%.
Harvey Weinstein, health and a plot to fix an England cricket match are on the front pages.
The president welcomed the North’s conciliatory response to his Thursday letter withdrawing from the summit.