Children as young as 12 months regularly use touchscreen devices, with most toddlers handling them competently by the age of two, research shows.
Swiping, unlocking or searching on smartphones and tablets were skills possessed by the majority of children in the study, the BMJ said.
It suggested that instead of being unhealthy for a child, time on touchscreen devices is not dis-similar to traditional forms of play, due to its interactivity.
Focusing on toddlers aged between 12 months and three years, the small study found 82% of parents owned a smart device, 87% of whom let their child play with it.
Half of parents (50%) said their child can unlock the screen while nine out of ten (91%) can reportedly swipe and two-thirds (64%) can search the device for features.
It found the youngest regular users of touchscreens were 12 months and most toddlers had mastered all three skills by an average age of 24 months.
The report, published in the Archives of Disease in Childhood, said: "Interactive touchscreen applications offer a level of engagement not previously experienced with other forms of media and are more akin to traditional play.
"This opens up the potential application of these devices for both assessment of development and early intervention in high-risk children."
It pointed out there were still issues about regulating the quality of the apps on the phone which cannot be overlooked.
"Many applications designed for infants and toddlers already exist but there is no regulation of their quality, educational value or safety," it continued.
"Some of the issues that arise with passive watching of television still apply."
The findings are based on 82 questionnaires, 47 (57%) of whom were boys.