Occasionally, just occasionally, we might weaken, Katie and me.
Actually, that's wrong. It should be 'Katie or me'. We never weaken at the same time. No joint weakeners, us.
One of us might, from time to time, think: "Maybe having kids would be a good thing." Perhaps it would be right for us to perpetuate the family line. It would be nice to have a mini-me, one of us might think every now and again. Someone to help through the trials of life. To be there for them; to support their dreams, build their expectations, teach them right from wrong, share in their successes, console them after their failures.
Then we'll have twenty minutes like we did in Sainsbury's this afternoon, and all such thoughts will vanish.
One child, not more than seven years old, was doing the "Mommy, although I've never seen xyz item in my life, having now seen it on the shelf it is now the very fulcrum of my existence and I can't live without it" routine. Mother, of course, was having none of it.
At one point he was shouting "I hate you!" at the top of his voice. To his mother. I went cold. It almost drowned out the sound made by Katie's fallopian tubes tying themselves in knots.
And he wasn't the only one. In the same way that a single dog barking will eventually set off all the neighbourhood hounds, this little angel was seemingly tapping into the squeal instinct of all children in a 400-yard radius.
"Sterilise me now," Katie muttered as we passed through the checkout. The cashier gave us a thoughtful look, shot through with: "I have to listen to this lot all day while you pair can go home and read the Sunday papers."
It's a shame really. People tell me I'd be a pretty cool dad. This is possibly because even now, at the age of 38, I've not moved on much from childhood in many respects. But the responsibility might be too much. Plus, I understand you're not allowed to use automatic weapons against them any more. Which is a shame.
So I have to rely on brother number 1 and his wife to deliver. If you'll pardon the expression. I quite like the idea of being the dissolute uncle who winds his nieces and nephews up and then delivers them back to mom and dad, over-excited and full of e-numbers. I'd be like the Yellow Pages - there for the good things in life, but not having to deal with the gritty disciplinary matters.
Moms and dads out there - I tip my hat to you all. I just don't think I can join you.