More than a third of American babies are tapping on smartphones and tablets even before they're walking or talking, according to a new study.
And by their first birthday, one in seven infants is using devices for at least an hour a day.
The results of the First Exposure and Use of Mobile Media in Young Children survey was presented to the Pediatric Academic Societies annual meeting in San Diego on the weekend.
The American Academy of Pediatrics discourages the use of entertainment media such as televisions, computers, smartphones and tablets by children under two-years-old.
Parents of children aged six months to four-years-old who attended a hospital-based pediatric clinic serving a low-income, minority community were asked to fill out the survey.
It was completed by 370 parents, with 97 per cent of them having TVs, 83 per cent tablets, 77 per cent smartphones and 59 per cent internet access.
Lead author Hilda Kabali said children younger than a year were exposed to the devices in surprisingly large numbers.
Fifty two per cent had watched TV, 36 per cent had touched or scrolled a screen, 24 per cent had called someone, 15 per cent used apps and 12 per cent played video games.
Most children were using mobile devices by the age of two.
"We didn't expect children were using the devices from the age of six months," Ms Kabali said.
"Some children were on the screen for as long as 30 minutes."