“So, how many brothers and sisters do you have?” asks the school mum I’m standing with.

We’d been chatting, this new friend and I, waiting for our six-year-olds to come barrelling out of class. I feel a thud of embarrassment at her question, but I force a smile and reply: “I’m an only child.”  

I say those four words with a shrug so they’ll appear weightless, but they drop between us like stones. I see on her face that peculiar mix of curiosity and suspicion. She can’t hide the look I know so well.

“Wow!” she says, “I wouldn’t have picked you for one of those,” and our conversation skids in a direction that makes me feel exposed.