LOUISVILLE, Ky.-- At what age should kids own smartphones? The 'Wait Until 8th' movement is sweeping the country, as parents pledge online to wait to give their kids smartphones until at least eighth grade, or 14 years old. The founders say some 20,000 families across 50 states have pledged. Child healthcare specialists agree 14 may be a good age, with limits.

One nurse practitioner says it's a good rule of thumb to limit screen time in general, to allow 1-2 hours per day for children five years old and younger, and not to allow any screen time for children younger than 18 months. 

"Younger children under the age of five, we've seen some problems with developmental delays because they are handed the tablet and they are not offered the chance to go out and explore," says Carly Oliver, APRN, with Norton Children's Medical Associates. 

"That is still a crucial time that they should be socializing with other chidren. They should be learning letters. They should be drawing. They should be going outside doing different activities," Oliver says. 

It can also be a safety concern, when kids take to social media and step into the realm of bullying and meeting strangers, she adds. 

'Wait Until 8th' explains they started their movement in 2017, when concerned parents felt pressured to get their kids smartphones as soon as first and second grade. On the movement's website, they claim that smartphones in the hands of young children change childhood, are addictive, are an academic distraction, alter children's brains, impair sleep, interfere with relationships, risk anxiety, depression, and cyber bullying, and can expose children to sexual content. 

Daniel Neeld is a parent of young children; his oldest is not yet five. He's already considered what age is appropriate for a cellphone, and says his kids will likely be getting flip phones that don't allow internet access, so they can connect with parents to carpool them to and from sports once they age into that. 

"Their minds are constantly going other places because that's what TV and screens does for them. It keeps them distracted and going other places," Neeld says, "we definitely set limits."