When we visit my sister’s house, there is a comfortingly familiar routine. We go in around the back door (someone is usually dying for the loo), put the bag up in the usual bedroom and then perch around the kitchen island and have tea. More trivial issues are dealt with first. On our last visit, it was that I had got a new car, about which there wasn’t that much to say other than – disappointingly – the car radio doesn’t have longwave. (I can use an app, but I like the sound of a scratchy BBC World Service. I find it a little romantic.)

The humdrum subjects are dispensed with quickly, because there are always far more important things to talk about; or more specifically, people to talk about. It goes on for hours, during which brothers-in-law, nieces and nephews, their partners and kids show up.

Sometimes, 11 of us go out for dinner, but on other occasions we stay at home. From an alcohol consumption point of view, this can be perilous. My niece has assumed the role of Wine Fairy – she always sits in the same position in the kitchen, adjacent to the open bottles, so that as we move from one topic on to the next, she pours everyone a fresh glass.

My kids are quite open with me about their lives. Too open, sometimesOpens in new window ]

Curiously, we rarely witness her doing this – we’re too busy talking and listening – and I’ve often suspected that she’s barely aware of doing it either. It’s as if her arms move independently while she concentrates on the subjects being discussed.

And on our last visit, the overarching subject was, as usual, family: the people who were there and who were not there. It radiated out of the house and around the world. Where is Son Number One now? (Bolivia). When will he be home next? (Early summer). How is Daughter Number One? And her partner? And Granddaughter Number one? How is their life in France? We covered Daughter Number Three’s music career, and a procedure Daughter Number Two had to have on her eye. Daughter Number Four told us about her part in a school play and her progress at swimming.

This was but a small portion of it. There is a wedding in May, a new home being renovated, a funeral that was attended. My grandniece and nephew bounced around in the background, occasionally chipping in with a question or an observation. And each new subject would prompt other stories, about people we knew or situations we had witnessed; until we came back to the next person on the list and a mysteriously full glass.

In the course of the night, dozens of people must have been mentioned. Technically, a family is a collection of individuals who are legally related to each other, but it’s more like a dynamic system, slowly growing over time and spreading across counties and countries. It’s a mental map of people, places and circumstances. Grown-up children form long-term relationships, and those people are absorbed into the collective, even if those relationships don’t always last. And they have children of their own. Come the summer, Daughter Number One will give birth to her second child, adding yet another name to the swelling list.

Parents don’t mould their children as much as they might like to thinkOpens in new window ]

And families intersect too. Herself talked about her parents and siblings, and in real time, we experienced the arrival of yet another person who will be asked after in the future. Just as the Wine Fairy started her evening shift, Herself’s younger sister in Dublin went into labour. Herself’s phone dinged with updates, and then, towards the end of the night, it rang: a baby boy had arrived. There was a flurry of excited calls. Then some pictures were delivered. As babies often do, he wore an expression of bafflement, like all the adults cooing down at him were quite mad. A new life. And as if by magic, glasses of prosecco materialised in front of us.