Joanna Fortune: My three-year-old son has started lying to me 

"Children start to lie around the age of three when they realise their parents are not mind readers and don’t know everything, so they test the limits by experimenting with the truth."

Pic: iStock

My three-year-old boy has recently started lying. For example, when he and his sister are playing, she’ll start crying, she’ll say he hit her and he’ll tell me she banged her head. 

I am 90% sure it’s a lie, but it’s hard to challenge him when I’m not certain, so he gets away with it. I’m struggling with how to respond to this.