"You're nearly 13 stone!" she said.
"I am not. I'm barely over 12."
"You fatass! You weigh more than me."
"Do not." Pause.
"Oh." Pause.
"Do. Well. I'm taller."
"And I'm eight months pregnant!"

Such was the stand-off at the bathroom scales on Thursday between myself and my girlfriend. It appears that we're not alone. It's just been reported that a survey of 5,000 men revealed that a quarter of us expectant fathers get so fat that they have to buy a special "pregnancy wardrobe" of tent-like lumberjack shirts, dungarees and elastic-waisted trousers.

I have yet to purchase such a wardrobe - but then, since I seldom if ever get out of my dressing gown these days, the whole thing is pretty academic. I'm certainly tubbier than I was.

Male pregnancy even has an official name: couvade. According to the baby manual we keep by the loo (be prepared: that's our motto), more than half of all expectant fathers experience some of the physical symptoms of pregnancy - mood swings, weight gain, late-night food cravings, dicky tummy, swollen breasts and, oddly, toothache.

That most of these symptoms are also associated with heavy drinking and childish attention-seeking is not, apparently, sufficient explanation. They are, we're encouraged to believe, somatic expressions of deep-rooted pre-parturition anxiety. Hmm.

My girlfriend is normally a fish and steamed vegetable kind of girl. I, on the other hand, favour meals that involve a simple and nutritious combination of white carbohydrate and highly processed pork product. Thus: pizza, hot dog, sausage roll, bacon roll, ham-and-cheese tortellini, sausage and bacon sandwich, pork pie, Cornish pasty, pork scratching sandwich.

Normally, we eat fish and steamed weggebobbles. But in the middle trimester, Alice miraculously went off fish and started craving bland carbs.

She suggested pizza. She even learned to say, with encouragement, "Mmmm! Sausages!" Who wouldn't have seized the advantage?

This is, surely, the true story behind the claims by a quarter of the poll's respondents that they "ate more food to make their partner feel more comfortable about her growing figure".

So I thought it would be wise to conduct a poll of my own.

I called my friend Umar, who's the father of twins and whose partner in her final month, as he put it, "had to be levered out of bed with an oar".

"Couvade my arse," he said. "More than half of men are greedy, lying bastards is what's going on there."