The report's authors said having children typically makes a man 'redouble' his commitment to his job.

London - Often it’s the tiny moments in life that catch you by the throat. Just recently, a friend phoned to tell me that she had become an aunt. “Can you believe it?” she said. “The baby looks just like my sister, it’s so sweet.”

And there it was. Those words “my sister”, something I’ll never get to say. And how I wish I could. For in the same way that some people yearn for a baby, as an only child I have long hankered to feel the singular bond that comes with having a sibling.

All my life, I’ve pictured these mythical sisters and brothers - given them names, imagined their personalities and our relationships, at once exasperated and affectionate, but, most of all, unique. As I get older, I indulge less in idle fantasies, but the emotions behind them remain every bit as profound.

Like many only children, my solitary status wasn’t intentional. Mom and Dad hoped to have at least one more baby after I was born in 1972, but it just didn’t happen, and back then you largely left things at that. And so I grew up as an adored “only” child - not spoilt particularly, but entirely secure in being the solitary object of my parents’ boundless affections.

That security, of course, is one of life’s greatest gifts, one I’ve appreciated ever more as I’ve got older and seen the toxic legacy of more unstable childhoods. There are reasons why studies show that single children are happier and more confident - we don’t grow up feeling we need to jostle for position for our parents’ love. Then there’s the more prosaic advantages, such as never having to share a bedroom and avoiding hand-me-down clothes.

Human nature being what it is, however, I’ve always wanted what I haven’t got. So, despite my contented upbringing, I grew up longing for not one, but a veritable gaggle of siblings with whom to share it.

At night, lying in bed, I would construct my imaginary family - a mixed bunch of brothers and sisters who had exotic (for back then, anyway) names like “Chelsea” and “Elliot” and who brought with them a sheen of glamour that was rather missing from our Seventies Lancashire terrace.

My best friend Lindsey, meanwhile, a twin who came in the middle of four children, had equally vivid fantasies of growing up in a sophisticated, silent household without her sister thrashing around on the top bunk.

But that’s the thing: while she loved coming to my house to enjoy its quiet and peaceful order, I longed for the noisy rumbustiousness of her childhood home, full of sound and activity.

I felt it particularly acutely on chilly winter nights, when Lindsey was dispatched home for her tea at 5pm on the dot and a long night indoors alone beckoned (although if nothing else those evenings certainly taught me self-sufficiency and the ability to pull off the perfect against-the- wall handstand).

Back in the Seventies, only children were a rare breed - at my primary school there was just one other “only” I remember. Now, however, it is a very different story.

The combination of couples having babies later in life and the soaring cost of living means that one child is becoming the norm, with 46 percent of families have just one. If the trend continues, they are likely to be in the majority in the next ten years - a fact I find saddening.

Growing up, I always felt something was missing - particularly in my teenage years. As battle lines were drawn over the wearing of make-up (not encouraged) and the acquisition of boyfriends (encouraged even less), I longed for the older sister who, in my mind, would have blazed a trail before me, or for the older brother who would support me in my fights.

On occasion, I even constructed swathes of imaginary dialogue based on these mythical figures: “You let Chelsea wear eye-liner”, or “Elliot’s got a girlfriend.”

By university, the fantasy sisters had been resolutely dumped in favour of a strapping gang of brothers - this time named after the authors and heroes I had developed a fondness for, like Rochester and Spencer - and who I imagined would descend into the college bar, leaving swooning women and envious men in their path, and boosting my social standing. Some of those feelings passed in my 20s, when I was far too busy worrying about the progress of my career and romances to think much about my family.

Flat-sharing with my two best friends from school strengthened an already close-knit bond to the extent that, in some ways, they felt - and still feel - like the sisters I never had.

As I hit my 30s, though, that yearning for flesh-and-blood siblings returned, prompted in part by seeing the way that previously fractious sibling dynamics had bloomed over the years.

Friends who were once consistently irritated by their siblings seemed to develop a new concordat, a bond strengthened by the recognition that friendships can come and go but family tends to stick around.

Then there’s confronting the reality of ageing parents (they won’t thank me for writing that sentence, but there we go). Mom is 69 now, while dad is 84, and while both defiantly resist the label “elderly” and are both, God willing, still in decent health, there is no denying they are no longer in the first flush of youth.

I worry endlessly about something happening to them - and how I will deal with it entirely alone. Because the fact is that while I have a loving husband and supportive friends, when it comes to family, as an only child you feel very, well, alone.

Should trouble knock at the family door there’s no sister or brother to dial and say “what shall we do?”, no blood relation of your own with whom to share these very particular worries and woes.

Of course, these things are complicated. I’m exceptionally close to my parents, particularly my mother. Many of my girlfriends have expressed envy at the easy intimacy of our relationship, and I wonder if it would have been the same if brothers and sisters were thrown into the equation - but, obviously, you never get to experience the other side.

I’m also acutely aware that siblings don’t come with guarantee certificates: I’ve known plenty of people fall out catastrophically with theirs, or at the very least feel woefully let down. When it comes to those ageing parents, for instance, the burden of responsibility tends, I note, to sit more heavily on the shoulders of one sibling.

For all that, I’d still like to have known how it felt to share my DNA. I know I am lucky to have grown up loved and secure, and I don’t wear that lightly.

But, as Christmas approaches, bringing with it the usual marital debate about where to spend it, with accompanying guilt about leaving my parents on their own, I find once again my thoughts turn wistfully to Chelsea and Elliot. We’d probably have fallen out by now, but I’d have liked the chance to find out. - Daily Mail