My son’s genetic inheritance is not something I think about often. He has 14 first cousins who are, like him, an Irish-English mix and our circular rigmarole of pronouncing their names while he plays with them should give him a grounding in the Irish language. My own Irishness only comes up when someone presumes me to be English, and for my son’s sake, I’m getting better at not reacting to this in that disheartened way one does when cinema staff say, ‘Will Pepsi do?’

We discovered that my dad was 100% Irish. Not 96 or 98, but 100%. It’s near impossible to get 100%

But questions of heritage rose afresh last week, when my sister Caoimhe got my dad an Ancestry profile and the whole family found ourselves rapt by our roots.

Dad had looked into genealogy in the 90s, tracing the family tree back a century-and-a-half, before the entire square-tentacled mass retreated into a freckled full house of illiterate farmers. There were some odd additions – our great (x5) uncle Edward Maguire was, supposedly, chief of police of Chicago – but for the most part it was rustic sod-botherers. The dream is that you’ll dig deep enough and find some improbable link to fame, fortune or foreign royalty. The best my dad could manage, back in the pre-internet days of library visits, census records and dusty birth documents, was to discover Derry’s famed Bishop Edward Daly, a man he’d been friends with all his life, was very slightly related to my grandmother, who’d babysat the infant bishop.

My father spent years at this and basically ended up with the same information he would have gotten if he’d had a guess while very tired. It was as if he’d spent two years opening a Kinder Egg, only to find inside a photo of the outside of a Kinder Egg.

So, I was under no illusions. I’m so offensively Irish, I could be one of those hilarious political cartoons you still get in British newspapers in 2019. I’ve spent my entire life being called Séamas O’Reilly, a name so unfathomably turf-scented, even other Irish people find it hilarious. But some small dream was alive inside. Maybe the new, modern, internet-enabled DNA-tracking methods would unveil my son’s link to Persian aristocracy. Or Somali pirates.

Alas, we found precisely the same Kinder Egg. Surpassing even our wildest disappointments, we discovered that my dad was 100% Irish. Not 96 or 98, but 100%. From what I’ve read, it’s near impossible to get 100%. Your ancestors would have to tether themselves to a tree and only have sex with people tethered to trees nearby, and repeat this for 1,000 years, to get 100%. But we managed it somehow.

There was one upside, in that the service came with a list of hundreds of new second, third and further removed cousins, all of whom are now capable of getting to know me, and thus my son, through this service: 472 of them in total. I’d better get him started on their names now.

Follow Séamas on Twitter @shockproofbeats