My daughter bawled the entire way, digging her heels into the sort of good ol’ fashioned public tantrum that really gives a parent their sea legs on a series of public trains. My wife was at a hen do, so I was taking the trip with both kids solo, to my brother’s house in Surrey, to hang with five of my siblings and their assorted children.

My kids have 16 cousins and watching them interact is as close as I’ll get to replicating the pleasant volubility of my own upbringing, since I don’t intend on having nine more children of my own. One of the quirks of my family tree is that it’s weirdly bottom-heavy, and I have more siblings than I do cousins.

When my parents were born, in the late 1940s, the average Irish woman had 3.48 children, so families of 10 or more were relatively common. Both of my wife’s parents, for example, are one of 12. By the time I was in school, however, this average had dropped to 2.83, and my friends usually had families of two or three. But since their own parents were frequently one of seven or eight, they all had innumerable cousins.

Across my entire education, I don’t think I was ever in a 30-person class that didn’t have at least two sets of cousins in it. This certainly made scraps more interesting, as any fight between two lads would be complicated by the fact that their intersecting groups of cousins would jump in to break things up or throw digs themselves. Perhaps it was this, and not any greater culture of maturity, which made such fights so rare. You might have a row with Emmett Duffy, the theory went, but you can’t take his whole family.

My family flipped all these trends. My dad is an only child and my mother’s four siblings only had eight kids between them. So I look at my children’s experience of extended family with quiet, jealous awe.

Nowhere was this more evident than the sight of Caitlin (7) taking my bleary-eyed little lout off my hands and convening an impromptu creche in the corner. There, Caitlin plopped her with her two youngest niblings, Ailbhe (3) and Clodagh (2), a rug, some books, blocks, cars and dolls, along with a disco light and some soothing music adding ambience to the occasion.

My son disappeared upstairs to play with his immediate peers and fan out over oldest cousins Finnian (17) and Malachy (16), whose status as teenagers means he regards them as little less than gods.

While I sit down, eat, and speak with my siblings, there is only one moment of muted alarm, when all the 5- to 9-year-olds launch a water balloon fight in the garden. This results in a great big splash near the barbecue and remonstrations are briefly mooted. ‘Leave it,’ I say solemnly, looking out at the unified mass of cousins waiting for a reaction. ‘We can’t take them all.’

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