The goal with cell phones is to have them as far away from your body as possible.  Use the speaker or hollow tube headset.  The regular wired headset sends the radiation up the wire, right into your head.  NOT a good idea!  And your children should never play with a cell phone.  Way too much radiation.

HEADSET – HOLLOW TUBE

These prohibit the radiation to travel up the wire and into your head.

https://www.amazon.com/EMF-Relief-Radiation-Headset-Microphone/dp/B00BY882R0/ref=sr_1_1?ie=UTF8&qid=1516047586&sr=8-1&keywords=hollow+tube+headset

This is another set highly recommended by an EMF expert:

https://www.defendershield.com/headphones?sscid=51k3_4osu4

More good info on headsets:

https://emfacademy.com/best-air-tube-headset/#best