If you look in the back of almost any women's magazine, you can see rather odd classified advertisements. Little colour blocks, a few centimetres square, usually with a picture of a baby and a headline saying something like 'Do Something Wonderful' or 'Could You Help Me?' or 'Please Change My Life'.

These are advertisements placed by women and couples looking for human eggs. They are trying to persuade women to become egg donors: to go through an IVF cycle and hand over a batch of eggs to the individual or couple who place the ad.

Strange, weird, a bit tacky, sitting there alongside the ads for plastic surgery and dating agencies? I might have thought so a few months ago. But I don't any more, because I'm one of the women who puts them there.

Egg Donation is the newest IVF miracle. It allows you to beat time, fools your body into embracing a young and energetic egg. I imagine the eggs to have the flat tummies and perfect skin of those years when the only issue with fertility is trying to rein it back. Me 20 years ago, in fact.

The success rates are astounding. With my own eggs, the doctor at the London Gynaecology and Fertility Centre told me and my husband, I'd have less than a 6 per cent chance of getting pregnant. Six per cent and falling with every month that goes by. With donated eggs, Dr Rami Al-Nasser tells me, the chance goes up to around 50 per cent.

It does this even if I'd had a premature menopause. Or didn't produce any eggs at all. Or if, like me, you spent your prime child-bearing years crossing your fingers and hoping that you'd meet the right man, but never quite achieving it.

Until two years ago I'd given up the idea of ever having any children of my own, and accepted that the closest I was going to get to being a mum was life as a godparent, a kind of proxy twilight version of the real thing with lots of fun but not many responsibilities. I like to think I'm pretty good at it, too.

And then there was work. Yes, I've got one of those jobs that you read about as 'role models'. My old school and sixth-form college both like me to go back as a living example of what a girl from round there can achieve if she puts her mind to it: we're a very long way from the posh establishments that turned out most of my contemporaries. They make a big deal about how I'm one of the first woman ever to do my particular job.

And of course, when I sit in front of a class of 15-year-olds I tend not to talk about sacrificing my child-bearing years to my bit of the media world. That's because it never felt like that's what I was doing. I was just following the course of female achievement that lies deep in my family mythology.

I was always aware of my mum's thwarted ambitions. She'd left school at 15, not really able to read and write, but with a burning (and unfulfilled) desire to 'do something' as she put it: film directing, war photography, running a business, you name it and she fantasised about it. She got as far as becoming a local teacher, no mean feat if you consider where she started.

But her real drive was reserved for her son and daughter and I stepped up to the challenge with alacrity. I wanted to do something exciting and all-consuming, with enough twists and turns to fill almost every nook and cranny of my life: the kind of thing my mother would have loved to do herself, but never got the chance to.

But there just wasn't time to do everything. And if I'd taken time out to have babies along the way, it's a lot less likely that I would have achieved so much professionally. Statistics show that the men who run my industry have the same number of children as the rest of the population, but the women have far, far fewer.

I was happy, well, happy-ish, like this for 20 years. Then suddenly, out of the blue, 'from down the back of the sofa', as our private joke has it, a man to properly, properly fall in love with came along. Even more amazing, he also fell in love with me.

Trouble was that I'm in my mid-forties and he is five years younger than me. He hasn't had the time, or the imperative, to go through that cycle of settling for being a godparent. He's the kind of man who would be a brilliant dad. He can't wait to give up his job and become a full-time father. It's unfair on him that my fertility permit ran out at exactly the moment when I most needed it.

If adoption was easier we'd do that, but it isn't. This gets harder as you get older, and by the time you are my age it's become really difficult, almost impossible if you are hoping for a baby or small child. The simple truth is that he deserves kids, and I'd love to give them to him, and if that means putting pleading adverts in Hello!, well that's what I'll do.

We're at a moment in history where it's possible, and while some people might think I don't deserve this, (shouldn't I just accept that I'm too old?) I know I'll do anything to give my husband the baby he craves.

If you want a bouncing youthful egg to replace your old tired-out ones there's not really an alternative to placing your ad. At least in Britain. In America, it's become a common way for young women to finance their way through college: the going rate for a batch of eggs is $4,000-6,000.

But in the UK, it is illegal to pay for human eggs. That means donation is the only way: that's why the ads are there. It's a huge thing to ask. Unlike giving blood, where there's less than an hour between walking in the door and that satisfying warm glow of having benefited humanity, donating eggs involves much more commitment. There are the pin-prick injections for a week, sniffing of hormones, a general anaesthetic to extract the eggs. Not to mention all the emotional and ethical issues. Nevertheless, there are women who think it all through and decide it is something they are happy to do.

Some women find friends or relatives to do it for them: either directly donating their eggs, or more commonly putting them into a pool, then getting someone else's in return. I thought about this route: but my best friends are all my age. We've switched as a generation from endlessly discussing contraception to endlessly discussing IVF. Their eggs are all as geriatric as mine.

There's the women I work with - and who work for me: but while I strive to be a good boss, and I can do a bit of office giggling with the best of them, it feels like far, far too much to ask.

And so it's back to the ads, unless we decide to go to America. We could just about afford it, although even on my salary it's a financial stretch. But we don't really want to do this. The Human Fertilisation and Embryology Authority has ruled that no money can change hands for eggs in the UK, and both of us really prefer the idea of donation, however complex and involved the process. Of life beginning not with a financial transaction, but with a gift.

I've started loving the idea of 'our' woman out there, walking around with the eggs that might some day become ours. My favourite daydream about her is that she has got three children, and loves the idea of more but her husband won't wear it: my grandmother was one of those. She used to have fantasies about finding a baby on a doorstep and not telling anyone. I know she'd have donated eggs if she'd been around and had any to give.

Or me, 10 years ago, going all gooey over friends' babies, but somehow not quite finding the time to go out and get a husband. I remember seeing the publicity, around the time when egg donation first started, and thinking maybe I should do it. Looking back I realise I was presciently pondering some kind of donation in the karma bank, hoping there'd be some around if I ever needed it later. But I didn't make the donation, and rushed off to a business meeting instead.

I'm looking at the first proofs of our advert in Hello!. The Logan Centre, which is the bit of the London Fertility Centre that deals with these things, recommends including a picture of a baby, and a direct plea from the heart, and so we have got 'Can you help us?' at the top. It doesn't talk about how we've ended up in this predicament, about doing something to make my mother proud, or our ages, or how it just took us both too long to find love. None of that. There's not really room.

· If you are under 36 and think you could help please call The Logan Centre on freephone 0800 389 9147 or register on www.logancentre.co.uk, quoting reference 17226