THERE IS a new descriptive term in vogue, and for all I know in Vogue: "glue baby."

A glue baby, not to be confused with the tar baby of Brer Rabbbit fame, is what a couple sometimes produces when the relationship is in difficulties. The theory is that the new baby will bend the troubled couple once again.

Recent media interest in the glue baby arose as a result of the earth shattering news that Mick Jagger's wife Jerry Hall is pregnant (at 41) with her fourth child. It is only a few months since Ms Hall was threatening a rather expensive divorce because of her husband's allegedly close bonding with some beautiful all purpose Italian starlet (a glue babe, perhaps).

I wish I didn't know all this, but I do.

Anyway, I went over to the Rotunda to ask veteran midwife Mildred Stirrup about the phenomenon of the glue baby. Was it just a media invention?

"Not at all" said Mildred enthusiastically. "We see the darlings regularly. Come and have a look."

Mildred then took me on a brisk trip through the wards, which were full of young couples doing the things young couples usually do with their new babies, i.e. caressing them and talking nonsense to them. Most of these beautiful infants were mewing piteously in appreciation. Were any of them glue babies, I asked?

"No, no" said Mildred - "you'll recognise one when you hear one.

Slightly confused by this, my next question was drowned out by the most ferocious bawling. "Here we are!" shouted Mildred above the racket. I now saw a tiny bloated redfaced creature, who seemed to be composed entirely of mouth, lungs and saliva, screaming at the top of its voice. Its pale parents sat apart on the bed, apparently in deep shock, and making no effort to quell the noise.

Somewhat shocked myself, looked at Mildred for an explanation. "You'll notice the parents are a little older than most of the others here", said Mildred with some satisfaction."

I reckoned this particular pair were both in their forties.

"That's right, and their last child was born 12 years ago. They were growing apart recently, so his is their glue baby.

Stunned, I told Mildred that I had expected to see a beautiful, placid child, with its parents holding hands and whispering sweet nothings to each other and the offspring.

"Obviously you misunderstand the glue baby concept", Mildred explained. "Glue babies are the noisiest and most difficult and troublesome and demanding babies in the whole world. If they were the placid creatures you imagine, then there would be little need for the parents to work together on looking after them."

"So the parents are brought together again by mutual misery?"

"Exactly" said Mildred with satisfaction. "Long days and nights of absolute horror and sleeplessness and unremitting toil. Mutual misery, as you say yourself - that's what puts the zing back in a marriage."

But surely, I suggested, the older children in a glue baby family would help out the parents in looking after the new arrival?

"God bless your innocence", said Mildred. "The older children are first of all deeply embarrassed and outraged at the notion of their ageing parents still having sex, never mind a baby.

So they don't help?

"Certainly not. And just as well too - otherwise the parents would get time to themselves and the whole concept of the glue baby would be undermined. Siblings understand this straightaway, and keep their distance."

But presumably the child grows out of this difficult phase?

"Not exactly. A glue baby is a glue baby for life, and its adhesive qualities actually increase right through childhood and adolescence."

The parents are stuck with it?

"With it and to it, you might say."

But what happens when it eventually grows up and leaves home, I asked Mildred? Surely the couple are then just as likely to separate as they were before it was conceived?

"A lot more likely, given what their glue baby has put them through. But the wonderful thing is that at this stage, they haven't got enough energy left to go through a separation, never mind a divorce. So they stay together."

All thanks to the glue baby?

"Precisely."

The glue baby is owed a lot, then?

"It is" said Mildred, "and it never fails to collect, either."