DD1 is 13, she has a friend whose mother seems to believe all sorts of rubbish. And they keep scaremongering. Ridiculous stuff.
The latest....if you keep your phone in your bra you get breast cancer
. DD1 keeps all sorts in her bra 
Before that it was if you tweak your nipples you get breast cancer. They seem deadly serious.
I am a GP and very scientific/evidence based, always very straight up an honest with my children.
This seems to throw DD1 and she rings to check! She is away on a school trip and has just texted to ask if its ok to keep her phone in her bra. I've told her she can keep the bloody thing wherever she likes and it wont give her cancer.