When I arrived at work yesterday morning, I felt exhausted. My five-year-old son's body clock has gone awry. Ever since Christmas Day, he has been waking up at 4.30am, insisting that it's time to get up. He's right as rain - we're looking increasingly haggard.

It's not just the sleep deprivation. It's simply the relentless pace at which a five-year-old boy lives. It's 7.15am and he wants you to play Thunderbirds while you cook his breakfast, prepare his packed lunch and hunt out his book bag.

After school he wants to play football with you in the park; back home it's time for a quick session of pirates with a friend from school, then tea, then bath, then bed. It's action-packed, it's fantastic fun and it's physically gruelling - even if you're only in your mid-30s.

Lynne Bezant is 56 and is expecting not one child, but twins. Yesterday she proudly displayed her bump on the front page of the Mirror newspaper, which celebrated this latest triumph of in vitro fertilisation (IVF) technology with a three-page world exclusive.

Because, if all goes well, this summer Bezant will carry her two bundles of joy into the record books when she becomes Britain's oldest mother of twins. (Elizabeth Buttle became the oldest woman to give birth in Britain at the age of 60, in 1997.)

At an age when most parents are either a) celebrating our children's independence or b) suffering pangs of empty nest syndrome, Bezant will be embarking on the wonderful journey of parenthood. Again.

Lynne, you see, already has a grown-up family with her civil-servant husband Derek, her junior at 55. They have three children, who are now themselves at an age when many people start considering having a family of their own. Jenny, 32, Andrew, 30, and 26-year-old Chris have given their blessing to their parents' fourth stab at parenthood. At least the twins will be able to play with the grandchildren.

In an editorial, which is worth reproducing in its entirety here, the Mirror eulogises older parenthood: "Even if life doesn't really begin at 40, it certainly doesn't end at 50 nowadays. It isn't just that people live longer - they are fitter, healthier and more active than their parents were at that age," it says. "So we should not be surprised that a couple in their 50s want to have more children.

"Some critics will say that Lynne and Derek Bezant should not be starting a new family at their age. Admittedly they will be well into their 70s by the time their twins finish school. But there are plenty of advantages to having children when you are older.

"Lynne and Derek have lots of experience of parenthood, for a start. They will be more relaxed than young parents and more able to deal with their youngsters' problems. In fact they will be better at bringing up their twins than many younger people.

"They love children. They know the hard work and problems involved. All the signs are that they will be perfect parents."

The story of Bezant would be intriguing at any time, but it has particular resonance right now, coming so soon after a story of another couple desperate for children. Lynne and Derek Bezant paid £5,000 for IVF treatment to give them the children they so wanted; Alan and Judith Kilshaw spent £24,000 trying to get their adopted twins out of the US.

Their stories are very different, but what has been striking in the case of the Kilshaws is the way in which the subsequent media storm has highlighted the needs and rights of children in the adoption process. For once, the focus is on them, rather than the needs and rights of their would-be parents.

Most adopting parents know this already - the rigorous assessment, the gruelling matching process, the careful monitoring which follows a placement. The needs of the child are always paramount. It doesn't matter how much you want a child, how long you've been waiting, how many failed IVF cycles or mis carriages you have had. The child's welfare and needs come first.

In IVF, however, the rights and needs of the parents seem the only consideration. If you can pay for it, you can usually get treatment. If they won't do it at one clinic because they feel you're too old, they'll suggest another that is more lenient.

Bezant, who lives in Oxfordshire, became pregnant after three eggs from a donor woman were fertilised, two of which were successfully implanted into her womb. She underwent the treatment at the London Gynaecological clinic, which is widely considered to be one of the most "liberal" fertility centres in this country.

Yesterday, Professor Ian Craft, director of the centre, was defending his decision to treat Bezant at a heated press conference at his plush Harley Street clinic. It was a happy ending to a tragic story, he insisted. The couple had always wanted a bigger family, but subsequent pregnancies had ended in miscarriage and, 20 years ago, still-born twins.

Which is very sad. And the Bezants deserve our deepest sympathy. But whether that makes it right to give donor eggs, which are notoriously hard to come by in this country, to a 56-year-old woman who already has three children is another matter. The donor in this case apparently knew her eggs were going to a woman of 55 (Bezant was still 55 when she was treated), but might it not have made better sense if those eggs had gone to a younger woman who has not yet had the fortune to have and bring up her own child?

Bezant might be the best mother in the world, but what about her two unborn children, what of their rights? Has their welfare been considered as the overwhelming priority?

When they are five years old, waking at the crack of dawn, running round the park, running rings around their parents, their mother will be over 60. When they are 10 and still at primary school, she will be 65; when they are 20 and having the time of their lives at university perhaps, she will be 75. No matter how far we push the boundaries - life begins at 40, life begins at 50, Joan Collins in her bikini and Rosanna Della Corta, who was 63 when she gave birth to a baby boy in 1994 - 75 is old even by today's standards.

The body charged with governing IVF, the Human Fertilisation and Embryology Authority (HFEA), yesterday insisted that procedures were in place to ensure that the welfare of any child was considered before treatment went ahead. The Human Fertilisation and Embryology Act 1990 provides that "a woman shall not be provided with treatment services unless account has been taken of any child who may be born as a result of the treatment (including the need of that child for a father). And of any other child who may be affected by the birth".

The HFEA inspects clinics annually to ensure that the requirements of the act are being met. But its critics say it lacks teeth. James Yeandel, HFEA spokesman says fewer than 1 in 1,000 IVF patients is in their 50s. If sufficient concern is raised, the case of the Bezants may be considered at the next monthly HFEA meeting.

Lord Winston, who runs a fertility clinic at the Hammersmith hospital, does not believe an age limit should be set. Each case has to be assessed on its merits and circumstance vary widely, but yesterday he was less than enthusiastic about Professor Craft's latest triumph.

"I can't comment on any individual case. On the face of it, it does not sound like a frightfully good decision. I don't think there would be many units where a woman like that would get treatment, but who knows?

"One would have to ask oneself whether that was not a misuse of a very valuable commodity (ie donated eggs). I'm jolly sure we would not have treated her at Hammersmith. We've always reserved donor eggs for women who have a premature menopause.

"People are waiting four or five years on a list for donor eggs. Very few women are prepared to donate eggs. Last year we treated about 10 couples using donor eggs. People who donate eggs on the whole imagine they are going to go to relatively young women."

Peter Brinsden, medical director at Bourn Hall clinic, near Cambridge, said he would not have treated Bezant, but that did not mean it was unreasonable of Professor Craft to treat her. "We have a policy that we do not treat women much over the age of about 59. I believe there are exceptional circumstances when it would be a reasonable thing to do.

"I would have said I know a man who might take a more liberal approach and I would send them to Ian Craft. I know he does not have the same rather conservative view that I have and is able and willing to take a rather more liberal view of a lot of these deserving cases. I respect that.

"It's something that's going to happen more and more often. Ian Craft has led the field in pushing the boundaries. Considering most women are now living to 85, these twins are going to be 30 when their mother dies.

"There's some evidence that having children increases longevity as well. I know there's a slight embarrassment at having a 65-year-old mother standing at the school gate when your are 10. But nowadays we have women of 35 or 40 picking up children at school when 10 years ago we never did."

Liv O'Hanlon, director of the Adoption Forum, is unconvinced. "This sort of thing makes me feel uncomfortable," she says. "For me it's something to do with that straying over nature's line. Who wants to be brought up by their grandparents?"

She says the case was in stark contrast to the internet adoption uproar, where the needs of the children were rightly paramount. "With IVF, I think the rights of a children are quite often ignored. They have to go through a short consultation but no more than that. They certainly don't have to go through 'are you a fit parent?' as you do in adoption.

"There's this sense that we should all be able to have what we want and we can't. I don't have a right to have children. All I have is a right to be fairly treated in my application.

"You have to question somebody's psyche that says at an age where she might naturally be a grandmother, that perhaps she would be better placed to take a more genteel route into grandparenthood, rather than put her body through this."

Bezant may have the best motives in the world for adding to her family at this late stage; she may be a fit, healthy 56-year-old who will be around not only to see her twins through their childhood, but to see their children too.

What this case has highlighted is the danger of using expensive interventionist technology to create children purely to satisfy the emotional needs of adults. Bezant told the Mirror: "When the children left home we were lonely and longing for more family life. We loved having them around us."

We use children to glue marriages together, to make us feel loved, to give us a purpose in life, to plug our emotional gaps. Whatever happened to their rights?