When I was a little girl, like most little girls, I used to love to draw a house with smoke that whirled out the chimney like telephone cord and a triangular-skirted mummy with her husband and two children. I saw her as the 'me' of the future. A blueprint for life. And I didn't much change that view until a few years ago, when I realised not everything works out like wax-crayon dreams.

Sure, at 43, I have the home, and there's often been a man in the picture, but as for children, there are none. Not because I ever had to face learning I was infertile. Neither did I postpone pregnancy to concentrate on a career, only to thud back down to earth on finding the egg-timer had run dry. It's just that while navigating my way through the thoroughly modern maze of serial monogamy, with all its deceptive bends and dead ends, I never reached the let's-make-babies stage with anyone. Not even when I was married - a brief, precarious union in which it seemed unwise to use parenthood as Polyfilla.

As for other long-term relationships, the men I loved weren't ready for babies. And never would I have got pregnant 'accidentally'. For me, that seemed an utterly joyless option. Nor was it in my nature to nag a man into nappydom. Even now, when I watch the sketch show Spoons, and that guy asks his girlfriend, 'Do you want a lager/lunch/lift to work?' and she screams, 'No, I want a fucking baby,' I positively cower. And hit the mute button. Maybe it's because she sounds so aggressive, so raw. Or maybe it's because she screeches the words I rarely so much as whispered.

I suppose I didn't dump ditherers because I wasn't a strategist. I simply saw baby love as something that, if you were fortunate, grew out of romantic love (which is why planning to have a child solo was, for me, always a non-starter). Perhaps too, while I wanted to rock the cradle, I simply wasn't confident enough to rock the boat. Fearful of swapping a love-in for a break-up, I hung on in there, hoping things would change. They never did.

And because that journey featured no ultimatum-filled arguments, no medica l procedures, no miscarriages and no mourning, it lacked a degree of drama. Thus, it became an impalpable, unacknowledged sadness. What a contributor to the book Beyond Childlessness (Rodale, £13) aptly christened 'a creeping non-choice'. Which is why I wonder if it's ever legitimate to seek sympathy, merely because my baby-making possibilities came to nothing.

'Of course it is, because it's actually a very big something,' says Liz Scott, fertility counsellor at the Assisted Conception Unit of the Lister Hospital. 'Many people are secretly carrying around a lot of grief about childlessness because whatever the cause - whether they never met the right man or perhaps IVF didn't succeed - it still comes down to the same thing... the loss of a dream child. And while most people recognise the grieving process when it comes to other life events - the death of a loved one or the loss of a home, even a career - society doesn't offer the same kind of support in these cases, and it can be a very insular, isolating process.'

Certainly these days, reasons for involuntary childlessness are many and varied. Whereas years ago, a diagnosis of infertility was accompanied by the slamming shut of a heavy door, now, with so many treatments and options available, that door is left ajar and a shaft of light shines through. But procedures aren't always successful. IVF can fail. Raised hopes can turn to razed dreams.

Others stories of childlessness are shaped by circumstance. I know a woman who met someone who already had children. He didn't want more and the question of whether to leave him in the hope of finding a partner who did, was complicated by her age - at 35, would she be happier staying put and accepting childlessness rather than risking loneliness?

Another friend starting seeing a divorcé who, although he had children, wasn't averse to having more, but had already had a vasectomy. She wondered when would be the right time to ask if he'd ever consider a reversal? Before they got serious? After? Would it even work?

Yet while there are many reasons why you might not have a 'Baby on Board' sticker slapped in your rear window (sometimes those things really do seem like a badge of honour), still, I find people make snap judgments. You're either pitied (poor thing, she must have dodgy ovaries) or judged (there's more to life than sports cars and spas).

In my case, as a journalist and shoe-junkie, it's usually assumed I have both expensively shod feet in the careerist camp, when in fact, with no family in the frame, it just seemed sensible to work in a creatively fulfilling job and pay off my mortgage.

There have been times when dealing with childlessness has hit home harder, often in the most seemingly inconsequential of moments. Like when someone wants to play the if-you-show-me-your-kiddie-snaps-I'll-show-you-mine game. When you tell them that unfortunately, things didn't work out that way, jokiness often ensues. Then, swiftly, it's dismissed. Perhaps they don't understand, having never walked in my Jimmy Choos. Perhaps they understand only too well - a world without those sunbeam faces on that clutched snapshot is not one they care to contemplate. And as is so often the case with things we dislike confronting, we ignore it.

However, it's hardly an uncommon experience. According to a report by the Institute for Public Policy Research (IPPR), when women in their early twenties were interviewed between 1982-84, five per cent said they didn't want children, yet four times as many were childless by their late thirties - that's one in five women born in the baby boom, a rate of childlessness double that of their mothers. What's more, it's projected that almost one quarter of women born in 1973 will be childless by the age of 45.

But as Rachel Black, co-author with Louise Scull of Beyond Childlessness, which explores the reflections of over 200 women's experiences of involuntary childlessness, says, 'Before writing the book, I felt society's and the media's silence contributed to my own sense of alienation and isolation surrounding childlessness. It's not a subject that lends itself well to "10 ways to solve your problem" type boxes because it goes to the very core of what it means to be a woman and no handy hints can resolve what, for many, takes years of work to reach a point where it feels OK.

'You don't hear many high-profile women discuss it either,' she continues. 'With the notable exceptions of Anthea Turner, Dillie Keane and author Hilary Mantel, I don't know of any others who have "come out". Yet celebrities seem to talk openly about children they've adopted. Somehow, this perpetuates the idea that involuntary childlessness is about failure. Something to be kept under wraps. A deadly secret. We need to break through the wall of silence.'

Recently, I felt compelled to try, and wrote a piece for Vogue about childlessness as a product of misaligned life moments. It was like dropping a stone in a glassy pond. Ripples spread out. Emails poured in. People passed it on to friends, who passed it on to friends abroad. I was inundated with messages saying thanks for being brave enough to talk about it. And while I have no wish to become the flag-bearer for the non-mothers union, I'm happy if it helps to start unravelling knots of pain.

'I've always wanted to tell people that I hadn't chosen to be childless,' said one woman, 'Yet I've felt I couldn't voice it. By being open, you've made it more socially acceptable.' How sad that she felt it's been such a taboo.

That said, currently the subject is being aired largely because some high-level number-crunching has been going down. The IPPR has suggested a demographic crisis could be on the horizon, with too few babies being born to support an ageing population. Secret agonies, it seems, could turn into a government problem.

One of the reasons cited for many women delaying conception and so having fewer babies, or no children at all, is that young mothers suffer a 'fertility penalty' and end up earning considerably less than their childless counterparts, which is the reason the IPPR is calling for greater family-friendly entitlements and more state-supported childcare.

Personally, I think the changing nature of relationships has played a huge part, too. I know plenty of 30-somethings who've clocked up a goodly number of longish relationships that never resulted in hitchings or hatchings. Unlike in my parents' day, we may jump into bed quicker but, if it's not working out, we rarely lie on the bed we've made. We surf for new dates. We search for upgrades. We expect more. And sometimes we get less.

With many more Britons living solo (singletons occupy nearly a third of all homes) and less financial interdependence between the sexes, dating has become ever more removed from mating. And if I'm honest, no matter how much I thought I wanted a traditional family set-up, armed with my own income and high expectations, I was easily drawn to alpha males who had yet to develop their nesting instincts.

Why, for example, did I spend nearly three years in my mid-thirties with a divinely handsome Frenchman eight years my junior, who I knew in my heart of hearts wasn't ready for marriage and children? Answer: because he was a divinely handsome Frenchman eight years my junior. Eventually, I lost him to a new job in Paris and a Porsche, as I always knew I would. But I choose to treasure the romantic times together, however fleeting, however unfruitful, and realise I must own - and honour - my past dating decisions.

But perhaps, then, rather than simply incentivising would-be mothers, we need to pause and consider the nature of modern relationships. Ask ourselves - both men and women - what we are ultimately seeking from them, not least because some of my 40-something male friends, who years ago would have run for the hills at the sight of a baby wipe, are all at sea being single and childless.

We also have to take on board our love affair with kidulthood. Stuart Gall, director of Biofusion, a company that's recently launched Plan Ahead (www.life-style-choices.com), a mail-order fertility test, says: 'Many people look much younger than their counterparts in previous generations and we've become so accustomed to opening the pages of Hello! and seeing 40-plus celebs with their babies, there's this perception that in fertility terms, we've become biologically younger too. The fact is we haven't and people need to understand that. Which is why we've designed this test to offer a predictive assessment of the number of eggs in a woman's ovaries because ovarian reserve is a key factor in a woman's potential to get pregnant. This can help her make an informed decision about whether to try for a baby sooner rather than later.'

Some geneticists predict that for future generations it will be more common for young women to remove and freeze some of their healthy eggs. However, Dr Gillian Lockwood, medical director of Midland Fertility Services, who headed the team that helped bring the UK's first 'ice twins' into the world, stresses it's not an insurance policy.

'I'm very happy to offer the procedure to my young cancer patients because this may be their only chance of having their own baby. But I would hate any woman who was in a position to have a child, and who knew that being a biological mum was a very impoprtant part of her life plan, to put it on ice in the expectation that it would be OK.

'However, I've had a few patients recently who've come to me at the end of a long relationship that they assumed was going to result in marriage and children and it hasn't, and now they don't want to be on a first date having to ask a chap about his thoughts on babies. Yet at the same time they know time is running out. And as I take the view that having options is one of the most empowering aspects of people's lives, and because biological time is so unkind to women, I would rather a woman was in a position to make those choices than finding that her choices had been taken away.

'It's important to realise these are not selfish women who want to "have it all",' she adds. 'Commitment-phobe men can be an extraordinary problem for many of today's women. Although interestingly, in many cases, when the man in a partnership was less keen to be a parent than his partner and then a baby comes along, he suddenly turns into the most doting of fathers.'

For me, it's too late for hi-tech hedging. What's been important however, is dealing with the feeling that I haven't fulfilled a fundamental part of being female. This may sound strange but I really wanted to experience giving birth, a visceral act that binds us to the cycle of life. When I see that stock soap opera scene of a sweating, swearing, screaming woman, knees to camera, I can't help thinking, it's odd I'll never know what that's like. As Liz Scott says: 'It's such a primitive drive, it connects to your sense of self. And this can take quite a knock after an infertility diagnosis or failure to have a child.'

However, where I differ from women with physiological problems is that while they're often angry at their bodies for letting them down, I used to feel the opposite. That I'd let down my fit, healthy body. That I'd cast a shadow of futility over my fertility. But over time, I've come to realise that identity - and femininity - aren't governed solely by the experience of being a mother, but by the courage to be yourself, whatever your situation.

I do think mothers could help non-mothers a bit more. Because in truth, it is often they who have, albeit inadvertently, hurt me the most. Particularly stinging is the breezily flung sentiment that it's not until you've had a child that you experience real love. Maybe. But when you love passionately - and try to live compassionately - that's a bloody hard assessment to accept with a cheery nod of the head.

I also get a bit twitchy constantly hearing how mothers get a raw deal at work. I know, I know they have genuine struggles, but the grass isn't always greener on the other side of the playpen. During 15 years working in offices, I was rarely able to take two consecutive weeks' holiday, yet other staff were on maternity leave, a couple for the third time in five years. I remember wanting to scream, 'Maybe I just need a couple of weeks off - a sabbatical even - to get over not having a baby.' But I didn't. I kept my head down and stayed mum.

The only occasions I do bite back is when, after expressing my horror at some catastrophic piece of world news - children being murdered, maimed or abused - women, who know I don't have kids, reply, 'Of course, this is so much harder to take when you're a mother.' I explain I'm expressing shock and sympathy on account of being human, which I rather hope is some kind of qualification.

Being shut out hurts. Being included helps. Enormously. As does straightforward acknowledgement of your unchosen situation. When my friend Deborah said in a completely no-messing fashion, 'Yes, it's a shame you didn't have children. You would have been a great mother,' it was truly liberating. An answer that helped me to start letting go.

And I have. Now, I'm ready to stretch my freedom until it screams for mercy. I want to travel. Take photographs. Write books. Polish my pointe work at ballet class. Flirt. Laugh. Take myself lightly. Indeed, as odd as this sounds, even if I had the chance to settle down, I would decline the offer. Because after years of low-level yearning, emotionally, the moment has passed. And in a spirit of acceptance, I think I've discovered a state of grace. And a taste for adventure.

Some things tug at my coattails still. Baby-cradling. Kissing an infant's vellum-soft head. And at the other end of life's story, I imagine when the time comes to ensure my parents are cared for, having had no children of my own, it may seem like I've skipped a stage. And raise the question, 'Who will care for me?' To whom will I leave my precious belongings/home/photographs of me as a child/vintage (by then) shoe-mountain?

Also tough are high days and Christmas holidays. However cool you are with it, there's always that nose-on-a-sweetshop-window moment. When I last stayed at Deb's for Christmas, I woke up in a teenager's bedroom beneath a Coca-Cola mobile with the words 'It's The Real Thing' spinning above my head. As family Christmases go, I knew it wasn't, nor ever would it be. But how I loved them for sharing it with me. And how I loved the younger boys for insisting I christen their Robosapien (Chico from Pop Idol got their vote, as you're asking).

What's more, when I drove away, after the two of them hugged me goodbye, I realised that while they may not be mine, that giant, wonderful, un-shy embrace was a very real thing after all....