MATHS was never my strong point but I’ve managed to work out that there are now precisely 73 days to go to the due date for our first grandchild, and the tension has been mounting – mostly over the baby’s sex.

As I’ve already explained, the parents – our eldest, Christopher (The Big Friendly Giant), and his partner, Lisa - know the sex but were banned from telling us because we wanted to be surprised.

However, in a recent column, I publicly declared that I’d worked it out.

There were two things which brought me to my deduction: first, Lisa had let slip that Christopher had bought a Batman baby-grow; then Christopher mentioned that Lisa’s dad had “spotted something on a scan”.

There was no point prevaricating any longer. “It’s a boy,” I told the world (or at least the readers of The Northern Echo).

Since then, I’ve been mentally preparing myself for the arrival of my grandson. I created an image of him in my mind, resplendent in his Batman baby-grow, and imagined all the things we’d do together as he grew older. I was even prepared to be Robin if it made him happy.

But then, last Sunday, events took a turn for the unexpected. The parents-to-be came for lunch and The Big Friendly Giant got a bit serious with my wife and I: “Look, do you think we could just tell you the baby’s sex once and for all? Quite frankly, it’s all getting a bit stressful trying to avoid letting the cat out of the bag all the time.”

“We already know,” I sighed. “You’ve already let the cat out of the bag – what with the Batman baby-grow and Lisa’s dad spotting something on the scan. It’s clearly a boy – I’ve already written about it.”

“Well, do you want to know for definite?” he asked.

“Oh go on then,” I replied, having been given a surreptitious nod of acceptance by my wife.

Christopher and Lisa smiled at each other and you could feel their tension lift as the BFG proudly announced: “Well, you’re wrong – it’s a girl!”

“A girl?” I mumbled. “But, but, but, what about the Batman baby-grow?”

He went on to explain that the Batman baby-grow had been bought well before he knew the sex and it would look just as good on a girl.

“But that’s ridiculous. Batman can’t be a girl – Batman’s a boy,” I found myself saying before realising I was starting to sound a bit away with the fairies.

Oh, and heaven knows what Lisa’s dad spotted on the scan but it clearly wasn’t what I thought it was.

So there we are. It’s not a boy after all. It’s a girl – with Chloe the favoured name as things stand. There’s time for the name to change, of course, but I like the sound of it.

And, if I’m totally honest, I’m really pleased it’s a girl. With three sons and only one daughter, it helps give the family tree a better balance.

Finally, we’ll be allowed to see the colour scheme of the nursery and we can start buying her toys and clothes.

I’ve already tracked down a really cute Catwoman baby-grow on the internet.

THE THINGS THEY SAY

FELLOW Dad, David Roberts, of Darlington, announced on Facebook that his little girl Katie had said her first word – “Archie”.

Archie is the name of the cat. Katie has yet to say “Daddy” or “Mummy” but David’s clearly being very philosophical.

“To be fair, all we do is feed her, bathe, her, and put a roof over her head, whereas Archie scratches the furniture, vomits on the floor, leaves bits of dead animals everywhere and presents an underlying risk of toxoplasmosis. Who can compete with that?” he asked.

THE THINGS MY MUM SAYS

MY dear old mum, going on 85, continues to bring smiles into my life every time I see her.

The Open golf championships were just starting when I called in to see her recently.

“I think Rory Bremner’s got a really good chance of winning The Open this year,” she told me, confidently.

“Don’t you mean Rory McIlroy?” I asked.

“No, Rory Bremner – he’s playing really well,” came the reply.

SHE’S been having a few problems with an eye infection lately, causing it to be inflamed near the tear-duct, but it wasn’t looking so red when I last saw her.

“Your eye’s looking a lot better,” I said.

“Well, I’ve been giving it a little rub now and again with spit on my finger,” she said. “I think it responds well to lava.”