The idea of a kid under 18 having a cell phone always surprises me, but in the world we live in, it's probably a good thing for a teen to have on hand. However, nervous parents who are always waiting around for a reply text will have a new app to try out. 

A father in England, Nick Herbert, invented ReplyASAP.

"Here’s how it works: When you send a message to someone using ReplyASAP, it sounds an alarm on their phone even if the phone is on silent. The message appears over whatever else they’re doing on the phone, and the alarm continues until the message is acknowledged. This allows parents to confirm that their child has seen the message, and prompts teens to reply to stop the noise and get back to whatever else they wanted to do on their phone."

But there's a caveat, it's only available on Android devices in the U.S. for now. Herbert and his son Ben are testing out an iOS/iPhone version that will hopefully be out soon.