Thinking about a third child, Kate? Prepare for a battle of Will

The Duchess of Cambridge’s joke on the family’s trip to Poland that she and Prince William should have another baby is unlikely to have been made entirely in jest. As the parents of any set of two children will attest, the debate over whether to have a third is a constant one – and each side’s case isn’t always made explicitly.

Indeed, I would wager that what Kate presented as a laughing matter is just as likely to have been the public eruption of private feelings (although, given her current glowing demeanour, this particular argument might already have been won).

For we commoners, it usually all starts when nappies and baby wipes finally fall off the shopping list – met with a sad pang by one half of a couple and a whoop of joy by the other. The latter can only ignore for so long the sighs of longing from the former, who will struggle to keep their hopes unspoken anyway.

All it’ll take for them to crack will be friends popping round with a colicky newborn. Before you can say “pass the muslin square”, your broody other half will be clutching that belching baby to their chest and saying: “What do you think, shall we have one more?”

There might be an unconvincing “ha ha” tagged on to the end but unless they’re talking about pouring you another glass of something dry from the fridge, you know you simply can’t put off the “shall we try for a third baby?” discussion any longer.

I speak from experience. No sooner had I cheerfully sent all our baby paraphernalia to the charity shop – we had two little girls at that point – than my old man started his campaign for baby number three.

While I was thrilled to find motherhood get that bit easier now that our children were a little older, he mourned the fact that we no longer had a cot to coo over.

“A third would be easy, with our experience,” he’d say, all memories of endless night feeds, nappy changing and cracked nipples somehow obliterated. Had he been the one fully experiencing them all, I suspect his recollections would have been a little sharper.

Giving birth would be a doddle, he would say, encouragingly – I’d probably be able to do it half asleep, having been such a trooper previously. I hadn’t even factored in the hellish pain of childbirth as a reason not to put myself through it all again – that became another one for the “reasons why not” column.

Other arguments against included having to fork out for a bigger car; more expensive holidays; the fact we shared two, not three, pairs of hands; and the terrifying idea that we might end up with twins, meaning double trouble in every respect.

Meanwhile, his “reasons for” were less practically minded. He focused mainly on how cute babies are, how wonderful their weight feels in your arms, and that delicious baby smell that not even the finest perfumier could begin to recreate.

In the end, I pulled what was supposed to be my genius move – booking us into a hotel for a child-free weekend of fun to remind him of more carefree times.

Of course, we had so much fun that I came home pregnant, the decision made for us.

We called our lovely little surprise Bridie. She’s 11 now, and I’m delighted to admit that I thank my lucky stars we have her every single day, whatever reservations I once might have had.