At least 40 per cent of American 2-to 4-year-olds have used a tablet or smartphone.
If there's one toy guaranteed to captivate toddlers this Christmas, it's the iPad. What's more appealing to a tot than blinking lights, fun sounds and touch screens that allow them to move things with the swipe of a tiny, sticky finger?
A 2011 survey of parents by Common Sense Media, an American organisation that provides media education for families, found that 39 per cent of 2-to-4-year-olds have used digital media such as smartphones and iPads. James Steyer, chief executive and founder of the group, is confident that number has risen in the past year.
To make things easier on parents, children and the iPad itself, Fisher-Price has a line of iPad and iPod protectors. For example, the "Laugh & Learn Apptivity Case," which comes with an attached rattle, is said to guard against "baby's dribbles & drool; teething; and unwanted pressing of home button". There's also the "iGuy", a free-standing case made of tantrum-proof foam.
But Steyer has stern advice for adults considering buying toddlers their very own iPads this Christmas: "No. Ridiculous idea."
Among parents and experts, the idea of giving a toddler an iPad is a fraught subject. There are some obvious drawbacks. For one thing, they're expensive -starting at $539 for the most recent version. They're also fragile. But the science on how the iPad affects young children isn't yet clear, and while some experts see them as developmentally inappropriate, others see some benefits to the technology - and not just in keeping a parent's sanity (if not guilt) in check.
The iPad has only been around only since 2010, so there hasn't been enough time to observe its long-term effects on kids, according to Michael Rich, director of the Cenre on Media and Child Health at Children's Hospital in Boston.
Rich, who runs the online advice column Ask the Mediatrician, says that apps on iPads and smartphones are limited as teaching tools since they typically focus on one type of learning - "skills and drills", which teach children to correctly identify the ABCs or to moo when they see a cow on the screen.
"What's more important at this age is learning how to learn rather than mimicking something," Rich says.
Moreover, studies show that children don't learn anything substantial, such as language, from screens - television, iPads, computers - until 30 months of age. The American Academy of Pediatrics recommends that parents hold off on any form of screen time until their children are 2.
A 2004 study in the journal Pediatrics showed that children exposed to television at ages 1 and 3 had decreased attention spans at age 7. It's a bit of a chicken-and-egg question, though.
"You can see how a kid who already has difficulty paying attention is put in front of the television to chill him out," Rich says. "It becomes a self-fulfilling prophecy."
Toddlers also sometimes struggle to translate what they see on two-dimensional screens to the three-dimensional world. (Check out the YouTube video "A Magazine Is an iPad That Does Not Work," in which a 1-year-old seems to get confused as she swipes her finger on a magazine, trying to move the pictures around.)
"Kids learn by doing, not by watching," says pediatrician Howard J. Bennett of Chevy Chase Pediatrics in Washington. "People once thought videos like Baby Einstein were good for kids too, and that's out now."
Giving children iPads to play with could also backfire, Bennett warns.
"Screens have this addictive quality, so when you take it away," he says, the kids "will probably cry".
Allison Mistrett, the founder and director of Leaps and Bounds, a paediatric occupational therapy practice, says she has seen children master Where's Wally? on an iPad but struggle to find their shoes in a crowded room.
Similarly, Rich says that many toddlers enjoy finger painting apps, but he questions whether the two-dimensional version trumps the real thing.
"The iPad does not give you that great feeling of paint squishing through your fingers," he says. "As much of a pain as that is for parents, think how much kids are learning about cause and effect. Not only can they draw pictures, they can make their hair all green and get a real reaction from mum."
Bennett has seen some practical benefits to iPads, however. Some toddlers watch movies while receiving shots in his office, which is helpful because distraction is one of the best tactics for dealing with pain at that age.
He generally advises parents to follow the AAP's recommendation that children over 2 should limit screen time to less than one to two hours per day.
"[Screens] should be a position of last resort," he says. "It's OK to let a toddler use a screen for 15 to 30 minutes once a day if a parent has to make dinner and has no other way to keep the child occupied and safe."
Tonia Sanders, a stay-at-home mother and blogger, doesn't see the harm in young kids' using technology. Each of her daughters, ages 3 and 6, has an iPhone, and the older girl got an iPod Touch when she was 2. Both girls also play with Sanders' iPad.
Sanders says that apps initially helped her older daughter master counting, learn letters and identify shapes. Now that she's older, she is interested in apps that show the workings of the digestive and nervous systems.
The idea that children don't learn from screens until 30 months of age does not square with Sanders' experience.
"When there's a child who can take technology and make it her own in 10, 15 minutes, I think there's something to be said for that kid. I wouldn't want to hinder her abilities," Sanders says. "This is the world we live in. Why stop children from learning about technology?"
Like many parents, Mistrett is more conflicted. She typically eschews battery-operated toys in favour of pretend and exploratory play and time on the playground.
"But the 1-year-old can already swipe to unlock my iPhone, so that's where I contradict myself," she says.
She also sees some benefits to touch-screen technology. All of the swiping can help develop fine-motor skills and hand-eye co-ordination, and such apps as "LetterSchool" can help with handwriting skills. The devices also motivate kids to stay focussed: "If you hand them the screen, they could go for hours," Mistrett says.
To minimise the temptation for children to do nothing but swipe, Mistrett and her husband have drawn limits for their children. She set up her iPad so that her 3-year-old son can access only his own apps. Mistrett allows him to play on the tablet a couple of times a day for 10-to-15- minute stretches.
Rich and other experts say that if parents are going to allow their children to use an iPad, they should sit and play along with them. That way, the parent is the teacher, rather than the technology.
"The fact that mum hugs the child when she gets something right, the tone in mum's voice - none of that can be conveyed by the iPad," Rich says.
This suggestion goes against what many parents use the iPad for: a "shut-up toy" - an industry term, according to Common Sense Media - because parents give them to their children in situations where they need them to be quiet, such as in restaurants, waiting rooms and aeroplanes.
Those are the types of situations when mother Monica Sakala allows her 3-year-old daughter to play with an iPhone, though not without some guilt.
"I like to think we could go out to dinner and she could colour or read a book," Sakala says. "We didn't have this stuff when I was a kid. We had to entertain ourselves. Sometimes I worry it seems lazy to whip [the iPhone] out."
As with most things, the key to iPad use in toddlers, most experts say, is moderation.
"What I tell parents is there are pros and cons," Mistrett says. "But if you're going to do it, look at stories and games together. Don't just hand it to them and walk away."
Mistrett suggests a few guidelines. Limit the amount of time children spend playing apps. Download only age-appropriate apps and games. And perhaps most important: Make sure the kid is blinking.