I wonder, for the millionth time, what I’d be like if this had been my life instead. If I’d lived the life I was actually meant to. Would I be toned and fit and an expert skier? Would I speak three languages? Would I still be a teacher? Would I still be me?

After the DNA test, I’d often find myself looking in the mirror, as if my reflection could tell me something about who I was. I needed to know where my eye colour came from, whose nose I had inherited, whose propensity for indecision and procrastination, because without knowing, I simply felt rooted to nothing, as though I’d been cut loose to float in this world like driftwood bobbing on the tides.

‘Jess! There is five of them,’ Luca says.

‘Are five.’

‘Look!’

I stand behind Luca and Léa and put my hands on their shoulders, watching the marmots scurrying about. Bigger, fatter squirrels, basically. ‘They’re pretty cute,’ I say.

‘Can we take one home?’ Léa asks.

‘Afraid not.’

‘Oh mais ils sont si mignons!’

‘They’d probably have your fingers off.’

‘What?’

‘Never mind.’

I try not to think about her too often. The other daughter. Mainly because it messes with my head. But also because I imagine her to be better than me. Prettier, more confident, more sorted. Would she be a soon-to-be divorcée with a stalled career and a clock ticking in her ears as loud as Big Ben? I expect not. I presume she doesn’t know – after all, I didn’t for thirty-seven years – and sometimes I imagine being the one to tell her. Smashing her life to pieces, making her feel how I felt after the tests changed everything. But then guilt and grief and confusion catch up with me and I want to protect her.

I don’t want her ever to know, because I wish I didn’t.

On Sunday, after Julia’s spent another long Saturday in the office, she tells me the four of them are going to the house of some family friends for an afternoon barbecue. As though she wants to remind me that I’m not actually part of the family, she doesn’t invite me to go with them.

‘Go and enjoy your day,’ she says. ‘We already take up far more of your time than we should.’

I suppose I should be pleased she’s spending a day with her children and I have Sunday to do as I wish, but when I see them all get into the car and drive off, I feel like she’s usurped me. A cuckoo in my nest. Jealousy catches in the back of my throat when I think of Léa’s delighted face, Luca’s excitement, Michel’s obvious pleasure that his wife is joining them for a second outing in two weeks.

The perfect little family, all together.