By Emma Mahony
London - Britain is fast becoming a nation of twins. Since the first test-tube baby was born in 1978, their numbers have been rising rapidly, with one in four IVF births producing twins or triplets. More than 10 000 sets of twins are now born in Britain each year, compared to 6 400 in 1980.
The rise of the IVF twin, though, may be stopped dead in its tracks if the findings of a Finnish study are adopted here in Britain.
The study suggests that implanting just one quality embryo is as likely to result in a successful IVF pregnancy as the traditional approach of using multiple embryos, especially for older women.
It comes at a time when the government's fertility watchdog, the Human Fertilisation and Embryology Authority (HFEA) is already looking at ways to reduce the number of multiple births, which it says are both dangerous and costly.
In 2004, the HFEA banned clinics from transferring more than two embryos to women who are under 40 years old and a maximum of three to those over 40, and its expert panel, chaired by Professor Braude of St Thomas's Hospital in London, is now expected to make further twin-busting recommendations at the end of this year.
Braude is keen to peddle the message that "twins are not a good idea in obstetric terms" and that "we are not naturally a species that produce twins".
But as a mother of twins who is also a twin herself, I feel a creeping sense of unease about these moves to cut back our numbers. It's hardly the first time that us twins have faced the disapproval of the singleton majority.
"Twins are seen as oddballs," confirms Professor Tim Spector of the Twin Research Unit, also based at St Thomas's.
With around 10 000 sets of twins on his database, he conducts research into the genetic causes of disease, comparing identical and non-identical twins to identify traits.
But after 13 years studying twins, Spector says he has also observed how the strange bond between twins can attract fascination and even jealousy in onlookers.
I can certainly confirm that, when you're a twin, a sense of "otherness" comes with the territory. For a start, there are the endless misconceptions to deal with. I could count on two sets of hands and feet how many intelligent people have asked me how I could have possibly conceived twins when "everyone knows that twins skip a generation".
For the record, genetic inheritance has never followed rational rules, and while my likelihood of conceiving twins was five times higher than the next woman waiting for her scan, skipping a generation? Perleeze.
Then there's that inevitable question, the one even the most unlikely-looking multiple siblings face: "Are you identical?" As I flattened down my pinafore dress at our first meeting, my headmaster at school asked both my twin brother and me this question. Nowadays, when people ask the same of my boy/girl twins, I reply with what I always wanted to answer back in my school days. "No, he has a willy, and she doesn't."
Even if your twins are identical, people still get it wrong. Caroline Watton, mother of identical twin girls Martha and Josie was stopped in a supermarket by an old lady. "Are your twins identical?" she asked. Before Caroline could reply the woman screeched: "Of course they aren't! One's asleep, and one's awake." The nation's biology teachers have a lot to answer for.
Given that my household is so twintastic, it should come as no surprise that I think multiple births are a Good Thing. To me, twins mean: never having to wonder if anyone will come to your birthday party; having more children with less pregnancies; and making full use of buy-one-get-one-free offers.
Non-identical twins only share only 50 percent of their genes, like a normal brother and sister, but there is still something very special about our bond.
Spector says: "Our studies have shown that a death of a twin has a greater psychological impact than the death of a parent or spouse."
When I was expecting my twins, my twin brother dropped to his knees before my swollen stomach and put his arms around my waist to press his ear against my navel.
"Listen Ems,: he said, "it's us in there", and I felt a huge hormonal rush of love that anchored me to the spot. It was as intense as the naughty tricks that we used to get up to as children, and that my own twins play now that they are five.
It is difficult to get angry with two toddlers who want only to climb into each others' cots, when you can remember doing exactly that yourself.
And when I told my mother how an afternoon nap had turned into a blizzard of talcum powder all over the floor (one twin had stood on the other's shoulder to reach it), she told me how she had once had to spend hundreds of pounds on a carpet cleaner when she found me and my brother making pies with zinc cream, aged two.
No one can overstate quite how difficult the first year of being a mother of twins is, though. I remember in the first couple of weeks gazing out of the window as the dawn broke having breastfed my two babies alternately every hour from 11pm, marvelling at how nightclubbing was the best preparation I had had for motherhood.
And not only the mother suffers. Sex is an impossibility in the early weeks when you sleep metres apart from your husband, and one by one the children take over the bed.
My husband announced in the third week that he would "sleep in a broom cupboard as long as it doesn't have babies in it".
When I wrote about the nocturnal shenanigans in our household for a newspaper, I received a letter from a sympathetic mother of twins who said that one night she collapsed on the landing when moving between beds, "and as I didn't belong in anyone's bed I wasn't missed and wasn't found until the morning".
For triplet mothers, the numbers just don't add up. In the first few months, someone calculated that 28 hours out of 24 hours in a day are needed to undertake the normal baby tasks, so they simply cannot cope without help.
But what twin and triplet mothers do have, which other mothers don't, is each other. In the last 20 years, the growth of twins clubs to support mothers has grown enormously.
Our local branch in south-west London holds regular coffee mornings where mothers of toddler twins can meet nervous expectant mothers and find out what are the best pushchairs to buy and which obstetricians to avoid.
At the last coffee morning I held, one of the seven triplet mothers in the club turned up bravely with her three charges, and asked us to all witness the phenomenon of how if one cried, the others all followed suit.
It didn't take long for the experiment to start, and the wailing of three miserable mouths, like baby birds in a nest, soon caused a stampede for the door.
The child psychologist Oliver James, a father of two toddlers himself, says that, while the early years of nought to three may be more problematic for twin mothers, "there may be a lot of bonuses, too. Many twins have very good relationships with each other and this may be a significant protection factor from adverse parenting and parents who row a lot".
Where twins are more vulnerable psychologically is in what James calls in his book They F*** You Up: How to Survive Family Life "the scripting of the family drama". This is where parents "script" children into identities and, especially with identical twins, the tendency to label one "outgoing" and the other "shy", or even "good" and "bad" is tempting.
This was certainly true of my twin brother and I, as my brother Dominic was pronounced "the sporty one" (and nicknamed "Dimmo Domo") while I was attributed with the brains. When I flunked my A-levels, there was shock and awe in the family, especially when Dominic sailed through with two As and a B.
My parents insisted that the papers were re-marked, not understanding that I had buckled under the pressure of what James might have termed fulfilling "my family script".
The fact that Dominic went on to win a bronze medal at the 1988 Seoul Olympics in Modern Pentathlon showed that he obviously felt more at home with his label.
Nowhere is this "scripting" more obvious than in the myths surrounding twins. Take, for example, the peculiar aura of glamour, menace and invulnerability that surrounded the Kray brothers during their East End gangland heyday in the 1960s.
Or the case of the mysterious Htoo twins, two 12-year-olds who lead a ragtag army of Karen hill tribesman in a jungle war against Burma in the late 1990s.
Father Augustine, a Thai missionary, reported that during one early skirmish, "there were just seven surrounded by Burmese troops. Somehow they fought their way out. Some believe that an army of spirits came to help them".
The twins success attracted other guerrillas to join them, and the myth of their special powers became exaggerated; even after their surrender, when numbers had dwindled to 20, they showed themselves lucky. The Thai authorities offered to relocate them to the United States.
Not all twins have been so lucky. During the second world war, Dr Josef Mengele, the Holocaust's Angel of Death, performed experiments on an estimated 3 000 twins who passed through the death camps of Auschwitz.
A survivor of the ordeal, Eva Mozes, remembers the chilling moment that she and her sister were plucked from their mother.
"As I clutched my mother's hand, an SS man hurried by shouting, 'Twins! Twins!' He stopped to look at us. Miriam and I looked very much alike. We were wearing similar clothes. 'Are they twins?' he asked my mother. 'Is that good?' She replied. He nodded yes. 'They are twins,' she said."
Eva was injected with a deadly virus and only survived because her twin sister was able to save her bread ration for a week, and smuggle it to her in hospital.
Twins loom large, too, in the the world of the arts, where it has long been recognised that the idea of a duplicate, or doppelganger, has a powerful place in our collective imagination. It brings to the fore the duality of human nature, the good and evil, how what lies beneath can be so different from the external mask.
Stanley Kubrick tapped into this archetype in The Shining, when he introduced the horror of the axe-murdered twin girls standing at the end of a creepy hotel corridor, beckoning a young boy to join them in the nether world.
Shakespeare, himself a father of twins Hamnet and Judith, also knew how to draw on this archetype in the Comedy Of Errors. Antipolus, in search of his identical twin brother, provides an analogy for all humans seeking to find their true selves.
While our fascination with twins remains as strong now as it was in the days of Shakespeare, at least we have come a long way from treating multiple siblings as a public spectacle, as with the Dionne quints, the five identical girls born in 1934 who were taken from their parents and put into a compound known as "Quintland", where special viewing facilities allowed over three million people to come and gawp at them over the years.
The girls were exploited in dozens of commercials and finally returned to the custody of their parents aged nine, but never fully recovered from the scars of their strange early life.
Barring such trauma and exploitation, Oliver James suggests that us twins may, in fact, even do better than singletons: "Eldest children are the centre of attention for a time, and then lose it; an only child finds it harder to grasp the viciousness of the playground and the office. Twins understand the politics of relationships and are used to having to establish themselves in terms of others in a favourable way," he says.
So, Professor Braude, when your group decides whether IVF mothers should still be allowed to implant more than one embryo, give a little thought to the future peers of those two-egg twins in the workplace.
In whatever size, shape or form they mature, they are probably more likely to make you a cup of tea and introduce you to the colleague you fancy sitting opposite. Just don't expect there to be any biscuits in the cupboard. They will have eaten them before their twin gets in there first.
- Emma Mahony is author of Double Trouble: Twins And How To Survive Them (HarperCollins).