I shall never forget the moment my father, reclining on a sun-lounger in our Hampshire back garden, stripey trunks on, chest-hair out, sat up and asked me: “Do you want to be circumcised?”

It wasn’t so much asked, as blurted out. A sudden rush of blood to his head. As if he’d been mulling over the suggestion for days, or weeks – months, even – and had finally steeled himself to the task. “Now! Say it! Quick!”

It occurred during a late-Seventies summer holiday; I would have been perhaps 14. The moment exists in my mind in such dreadful clarity: myself wandering around the lawn, killing time, he on the patio, gazing up towards me, shielding his eyes. A perfectly reasonable day, bulldozed into hideousness by his ultra-personal, baseless query. Bewilderment, hand-wringing embarrassment, The Fear. I imagine the sky darkened.

A little background, for context: never did we discuss sexual matters, my parents and I, nor even one another’s genitalia. No one hugged; love went unspoken but emerged through kindness, compassion and those ineffable qualities of the family unit. My parents grew up after the First World War and endured the Second. The only stiffness their upbringings would entertain out loud was that of the upper lip.

So “Do you want to be circumcised?” is up there with “Are you a homosexual?” as the most memorable query my father ever put to me.

He might as well have said: “I’m wearing your mother’s pants under these trunks. Would you like to see them?”

I didn’t reply. I couldn’t reply! Shock had rendered me mute. But Dad had not finished. Oh no.

“It’ll make it bigger,” he adds.

Once again. It’ll. Make. It. Bigger.

(It won’t.)

It’s feasible that I was clinically dead for several seconds afterwards. I recall mumbling something – “Nmph”? – then walking quickly indoors, unattractively, like they do in those Olympic walking races.

I had no idea at the time – and anyway my thought processes were resembling wide-eyed woodland creatures in a tumble-dryer – but medically, that is total bollocks. Circumcision does not make a penis longer – if anything, the opposite. How could anyone base the potential excising of their son’s sorry foreskin on quack theory?

Consider his words now and the implications are unavoidable.

My Dad had been thinking about my penis. Quite a bit. Having done so, he had decided that it was either (a) aesthetically too florid-looking, or worse, (b) too small. When had he last seen it, to make such a judgment? Had he been spying on me? What did he consider ‘too small’? Was my penis too small? Is it too small?

I mean. Fuck.

Discussing any matter of sexuality with one’s offspring – I am a father myself, to an 18-year-old son and a short daughter, so I should know – is a minefield. The more you try to prepare yourself, the worse it becomes. Sentences, ways of putting things, shape and reshape themselves until the words lose all meaning; the brain starts to pound. That’s where my Dad’s head was, on Circumcision Day.

Concerning my own son and sexual matters, that unfortunately is where my head lives too. I have never once considered asking him whether he’s content with all 100 per cent of his penis, or whether he’d prefer a tad less. Neither did I tell him of the birds and the bees, nor can I discuss girlfriends with him entirely comfortably. (Indeed, he’s far easier voicing all that than I am.)

Clearly there is a lesson in there somewhere.