Daddy is mowing the lawn when his young son comes running out of the house calling to him. “Daddy, daddy, what’s sex?” asks the boy.

For a moment dad is dumbstruck but then decides that if his son has asked the question, then he must do his best to answer it. For the next few minutes dad talks about the birds and the bees, then human relationships, love, the sex act, having babies – in fact he does a pretty good job of covering every aspect.

Eventually he comes to a stop when he sees how oddly his son is looking at him.

“Why did you want to know?” he asks.

“Well, Mummy said to come out and tell you that dinner would be ready in two secs.”