A whopping 40-percent of kids 2-4 years have used a smartphone, tablet or video iPod., that's according to a new study by Common Sense Media.

And in one in five cases, parents said they gave their children the devices to occupy them while they were busy or ran errands.

Some are calling them high-tech pacifiers for toddlers.

The devices offer thousands of apps specifically targeted to babies and toddlers, including interactive and memory-matching games, sing-along nursery rhymes, and more.

There's even an app for newborns that plays white noise, a womb-like whoosh, that parents claim soothes crying babies to sleep.