Doctors Panayiotis Zavos and Severino Antinori claim they are ready to embark on the greatest human experiment of our age. They say they will attempt to clone a human being before the year is out. Most people think the objections to this are ethical - human cloning would create many moral dilemmas.
There is another question that few ever ask: is the science actually ready yet for cloning healthy humans? Horizon follows the latest research, which has led many scientists to believe that Zavos and Antinori's plans to clone the first human could end in tragedy. The programme also meets couples like Matthew and Desirée Racquer (above) who think cloning offers them the only way to raise a child who is truly their own.
Dr Lorraine Young at the Roslin Institute laboratoriesFor decades, cloning remained within the realms of science fiction. The idea that instead of combining a sperm and an egg, a new human could be made from a single cell taken from an adult, seemed completely absurd. But that all changed in February 1997, when the Roslin Institute (right) introduced the world to Dolly the sheep - the first animal cloned from an adult. Ever since Dolly, scientists have been continuing to experiment with cloning animals. So far, they have succeeded in cloning sheep, cattle, pigs, goats and mice, fuelling the belief that humans could be next.
An unreliable procedure
But even Dolly's creator, Professor Ian Wilmut, is concerned that beneath the veneer of success lies a disturbing reality. Most cloning attempts on animals so far have resulted in failed implantation or abnormal foetuses. Of the animals born alive, some soon die of catastrophic organ failure. Others appear to be healthy for weeks or even months, then die suddenly, sometimes from bizarre new illnesses which do not occur in nature.
Years of painstaking work are only now revealing some vital clues to what is going wrong. Horizon talks to the scientists who have uncovered new evidence, suggesting that the process of cloning itself causes subtle errors in the way genes function. These random errors may be like a timebomb inside every clone, causing some of the strange - often fatal - problems. There's no reason to think cloned human babies would fare any better. According to embryologist Dr Susan Avery, death might be the best outcome for many human clones. If they survived, they would suffer from catastrophic illnesses that modern medicine is powerless to prevent or cure.
Test tube troubles
Dr Zavos claims that these problems are the result of the still unsophisticated methods being used by animal researchers. Using advanced in vitro fertilisation ('test tube baby') techniques, he claims that he will strive to make human cloning safer than natural reproduction. Now though, it seems that some IVF procedures themselves are being investigated for possible harmful effects on the long term health of children. Professor Gerald Schatten of the University of Pittsburgh reveals evidence of these risks, which could be magnified in cloning.
Most reproductive specialists believe that the danger to any human born by cloning is enormous. But the would-be human cloners are determined to clone a human baby. If they proceed, they may be courting tragedy.
Source: BBC Horizon
REPORTER: Rome's Medical School has never seen anything quite like it.
REPORTER: Prof Severino Antinori said hundreds of couples have already agreed to take part in his experiment.
NARRATOR (STEPHEN MANGAN): These two scientists claim they're about to do something that many believe is both dangerous and wrong.
DR PANAYIOTIS ZAVOS: The genie is out of the bottle.
NARRATOR: Something so extraordinary that it could alter the very evolution of our species.
PANAYIOTIS ZAVOS: We don't need any permissions from anybody.
NARRATOR: They say that next month in a secret laboratory they will try to clone a human being.
DR SEVERINO ANTINORI: We'll be careful.
NARRATOR: But in the last few months new research has revealed hidden dangers so terrifying that most scientists now believe human cloning would be disastrous. So is science really ready to clone a human?
DR WHO (TOM BAKER): Can I have a word with you? Where are you going?
LEILA (LOUISE JAMISON): I think I'm needed elsewhere.
DR WHO: K9, cloning techniques, give me a rundown, state-of-the-art so far.
K9: Cloning. Cloning is replication, making a copy of an individual from a single cell of that individual. Clones - clones retain characteristics of original organism.
DR WHO: Go on, go on!
NARRATOR: Cloning would be a completely new way of making a human being. Instead of the combination of father's sperm and mother's egg that makes each of us unique, cloning will create a baby from a single cell from a single person. The clone will be an identical genetic copy.
PROF GREG STOCK (University of California, Los Angeles): Cloning does not create anything new. It creates a genetic copy of an existing being. People have a, an extraordinary emotional reaction to cloning because it's, it conjures up all sorts of images: duplication, the images from science-fiction of factory reproduction and it really makes them face the notion that our technology is going to allow us to intervene even in the most intimate processes of our lives, so this is really big stuff.
NARRATOR: Whatever its opponents say there are people who will try the new technology. For infertile couples who cannot make babies with sperm and eggs, cloning is a medical breakthrough that could give them children of their own. Desirée and Matthew are willing to take the first steps into this brave new world. Two years ago cancer treatment left Desirée infertile.
DESIRÉE RACQUER: I look at Matt and I look at, you know, people our age and they're just getting started with their family and their wife is pregnant and they're so excited, you know, it's their first baby and it, it makes me sad to think that I will never be able to do that for him.
NARRATOR: In desperation they tried to adopt a child, but at the last moment the arrangement fell through. Anxious for another solution Desirée began searching the Internet. There she found what she had thought impossible, an extraordinary new way to have a child genetically their own. This was cloning.
DESIRÉE RACQUER : And when he got home I just met him at the door, I was so excited, you know, look, look, there's you know something out there different than what we found.
MATTHEW RACQUER : I think at first I thought she was just full of it and it was just a big hoax...
DESIRÉE RACQUER: Hoax.
MATTHEW RACQUER: ...on the Internet and then...
DESIRÉE RACQUER : That's what I thought too.
NARRATOR: But the more they found out, the more convinced they became that cloning was a real possibility and the only one that could give them what they wanted.
DESIRÉE RACQUER: And then I realised wow, you know, something else that, that might help us, so it, it was a very good, good discovery.
MATTHEW RACQUER : Just like another light at the end of the tunnel.
DESIRÉE RACQUER : Yeah, yeah.
NARRATOR: The men who claim they can help couples like Desirée and Matthew travel the world to champion their cause. Last summer Dr Panayiotis Zavos came to Oxford to put the case for cloning to some of the biggest names in British science.
PANAYIOTIS ZAVOS: Good evening, good evening everyone and welcome to Oxford Union debates. Everybody that comes to see us as infertility specialists wants a child yesterday if at all possible and the second thing is they want a healthy child, therefore...
NARRATOR: Dr Zavos is not a cloning expert, but at his fertility clinic in Kentucky he already makes a living from making babies and at $50,000 a try, cloning will be a lucrative business.
PANAYIOTIS ZAVOS: ...and therefore everybody needs to understand that we are responsible individuals understanding the needs of people that are not here tonight. Infertility patients don't rise like everybody else that rises here and wants to make a point. It's a silent disease and therefore we need to address that.
PROF ROBERT WINSTON: Madam President, ladies and gentlemen...
NARRATOR: But many scientists are not impressed.
ROBERT WINSTON: ...unethical. What you are doing is incredibly disreputable. What you are doing is utterly appalling. Do you know, I don't mind if you clone a human being actually, because I think you would get the full force of the law when inevitably you produce an abnormal child and the parents of the child will sue you through the court and God help you when that happens and you deserve the full force of the law, whether it be in the United States or in Italy.
NARRATOR: What Dr Zavos and his colleagues are proposing has so far only ever been done in animals. They will take an egg from a woman and remove its nucleus, the part which contains her DNA. They will be left with a hollow egg. Next they will take a cell from the body of the adult who is to be cloned. It's from this cell that they will make a new human being, an identical genetic copy.
GREG STOCK: The way an adult would be cloned would be you have to take a cell from that adult and you might be able to get that from a tissue swab in the cheek or from a scraping of skin or from a little biopsy and the cell would then be taken to the laboratory.
NARRATOR: Once they have selected the cell scientists will take its DNA and insert it into the empty egg. Then they will have to stimulate the egg to begin to grow. They might use an electric shock and add chemicals, the methods used in animals. No one understands how or why, but this process should switch the adult cell back to become the very first cell of life. The new embryo will be grown in a dish for a few days, then implanted into a woman's womb where it might grow into a human being. This human would be a clone.
GREG STOCK: Nine months later you would have a child and the only difference between that child and a child that had been conceived normally would be that the child would have the exact same genetic constitution as the individual who donate, donated the original tissue, the original nucleus.
NARRATOR: It's the promise of that identical genetic constitution that makes some people see cloning as a way to raise the dead. Earlier this year Al Powell's mother was diagnosed with terminal cancer. Devastated, he found hope in the idea that cloning could give her a second chance.
AL POWELL: I followed like the cloning controversy and then it just kind of like I start thinking about, you know, the possibility of cloning my Mom 'cos at that time this is just 2½ months maybe before she died, I realised she wasn't going to live that long.
NARRATOR: But to be able to clone their mother in the future they would have to get a tissue sample from her and have it frozen, and they couldn't find a scientist willing to do the job.
AL POWELL: It had come down to where my brother and I were going to do it after my Mom passed away and so we contacted someone who told us how to do it. You could either do it from like the upper arm or from her, from her leg, from her lower leg and you could actually do it with like, you know, scissors, everything would have to be sterilised, you'd use gloves.
NARRATOR: Fortunately they didn't have to and a doctor agreed to perform the vital operation properly.
AL POWELL: I just went in, just my, just by myself with a doctor and we actually had six phials. Then he took some, some tissue samples, you know, little, you know he cut 'em up and put 'em in the samples and then sealed them. We actually then, next day, we FedEx'd them to this laboratory.
NARRATOR: Now six pieces of Al's mother are frozen in a vat somewhere in America waiting for the era of human cloning to begin, but until recently many thought that era would never come. For over 30 years researchers had been trying to clone animals from adult cells. It had never worked. By the 1980s many leading scientists were saying it was impossible.
GREG STOCK: If you asked some geneticist 25 years ago whether we would do, be doing the things that we're doing today, even whether we would know the sequence of the entire human genome, they would have said no way that's going to happen in that period of time.
NARRATOR: But in February 1997 the age of cloning began with a sheep called Dolly. So far cloning has been successful in sheep, cattle, pigs, goats and mice. But the scientists doing it were never aiming to make human babies. Instead they see cloning as a new kind of farming, a way to create animals genetically engineered for our benefit.
ACTUALITY AUCTIONEERING DIALOGUE
NARRATOR: In the next few years this cattle fair might be trading animals which make human anti-bodies, or medicines, in their milk. This will be possible because of cloning. Genetically engineer one animal and you'll be able to clone a whole herd. And away from the hype about cloned babies mainstream scientists do also see good reason for cloning from human cells. They're hoping to treat incurable conditions like Parkinson's or heart disease by growing new brain or heart cells cloned from the patient, but behind all the optimism lies a stark reality. At the Roslin Institute, the lab which made history with Dolly, scientists have found their success very hard to repeat. For every one hundred cells injected into eggs typically only two or three clones will be born alive. Most will either fail to start growing into an embryo at all, or fail to implant in the womb and in the few cases where pregnancies begin many of the cloned animals die before they even make it to birth.
PROF IAN WILMUT (Roslin Institute): It can happen at any time during the development of pregnancy. Sometimes my colleagues would see the placenta going wrong, sometimes things would look perfectly normal, you'd be expecting a live birth within a few days and the, the lamb would die, the foetus would die because of some abnormality that you couldn't detect by ultrasound.
NARRATOR: Then there was the strange case of a cloned lamb which began life seeming perfectly normal.
IAN WILMUT: We were very excited by the fact that it was born naturally and was essentially very healthy, except for one thing which was that it panted all the time, just the same way that you and I would if we'd been running for a hundred yards, but all of the time night and day and obviously my veterinary colleagues took advice from other vets and from the Children's Hospital and tried any of the treatments that were recommended, but unfortunately none of them were able to correct the condition.
NARRATOR: And it wasn't just the Roslin lambs. Around the world some clones were dying of bizarre, inexplicable conditions.
IAN WILMUT: In cloned animals of all the different species there've been an enormous variety of, of different abnormalities. In the kidneys, the livers, the hearts, the blood vessels, the skin, the musculature of the, the body wall...
DR LORRAINE YOUNG (Roslin Institute): ...heart defects, limb abnormalities and facial abnormalities, but not...
DR GERALD SCHATTEN (Magee Women's Research Institute, Pittsburgh): ...the newborns have been born with their insides on the outside. We know that they have immunological problems, they have pulmonary problems, they have cardiac...
LORRAINE YOUNG: ...within hours of birth they tend to die...
IAN WILMUT: ...the musculature of the, the body wall, the brain, the face. I think...
GERALD SCHATTEN: ...some of them are able to breathe, but only breathe if they're on oxygen. Whoever heard of a calf grazing with oxygen on its back?
NARRATOR: Scientists had to get to the bottom of the mysterious deaths. They took the organs from clones which had died and prepared tissue samples. Pathologist Susan Rhind was one of the first to examine samples from dead clones under the microscope. What she has found is shocking.
DR SUSAN RHIND (University of Edinburgh): These lambs showed serious problems with their breathing so an obvious place to start looking was in the lung tissue itself to see if there was any problems there and if we look at a section here from a normal lamb and what we've got here is a large airway bringing the air down into the lung and if we can focus on this structure here which is a blood vessel and at this same magnification move on to looking at the lung from a cloned lamb, we can see instantly how different they are from the normal. We have a blood vessel which is massively enlarged and the size of this is really far beyond what one would normally expect in a normal lung.
NARRATOR: The more samples she looked at the worse the picture became.
SUSAN RHIND: This next slide here is too big to even put on the screen. I mean this is, is an even more massively enlarged vessel.
NARRATOR: The lambs' hearts couldn't cope with the task of trying to push blood round gigantic vessels 20 times bigger than they should be. These clones had no chance.
DR HARRY GRIFFIN (Roslin Institute): It's not possible to pick up these abnormalities by ultrasound and carry out...
NARRATOR: For the Roslin Institute Science Director, Harry Griffin, the fate of clones like these should sound a warning to anyone who wants to clone a human.
HARRY GRIFFIN: ...told us that this animal was suffering from a major cardiovascular problem that was untreatable. We put this animal down because we didn't want it to suffer any longer. Now if any of you are tempted with the idea of cloning a human being, and I would ask Dr Zavos this question, given that sort of defect what would he do with it?
PANAYIOTIS ZAVOS: All those experiments that is done in animals today are obviously done on a hit and miss type basis...
NARRATOR: But Dr Zavos insists that long experience of making human babies makes him a safer pair of hands.
PANAYIOTIS ZAVOS: ...Dr Zavos has been producing children for the last 25 years and not one single baby, abnormal baby was born ever and we don't intend to have one single child ever be born from such an effort, ever. Lambs are lambs, humans are humans. Dr Griffin has to realise what the difference is and that's what the difference is. Thank you.
HARRY GRIFFIN: The difference in this case of course is that in the UK and elsewhere we're allowed to experiment on lambs, we're not allowed to experiment on human beings and the point that I'm...
NARRATOR: Dr Zavos may be confident but the more the scientists examined different organs from dead clones the worse the picture became. They found a bizarre array of deformities never seen in nature. On the left is a cross-section of a kidney from a normal lamb, on the right, on the same scale, are cross-sections from two clones. These kidneys are shrunken with much of their tissue missing and there were other problems. A normal lamb's liver is mostly made up of healthy liver cells, seen here in pink, but in the clones most of the liver was made of strange, unspecialised cells that couldn't function as liver cells. The implications for human cloning were terrifying. If a human baby born with these kinds of defects were to survive at all many scientists now believe it would suffer devastating illnesses unknown to medicine, but Dr Zavos and his Italian associate, Dr Severino Antinori, are confident they can produce healthy human clones.
PANAYIOTIS ZAVOS: We have no intentions to step over dead bodies or deformed babies to accomplish this.
SEVERINO ANTINORI: I'm not sure to permit to continue the pregnancy if there is some abnormality.
NARRATOR: And the prospect of having an abnormal child is not enough to deter people desperate for a family. Couples like Desirée and Matthew seem to have no idea how profound the problems might be.
MATTHEW RACQUER : But even if there was something wrong with the child we wouldn't toss the child away. We'd both still raise it to the best of our ability and treat it as a normal child.
DESIRÉE RACQUER : I would be like, me, if I could get pregnant myself and we found out at five months that it, you know it didn't have an arm or a leg or something, I mean then telling us we could abort it I don't really think we would. I don't see us being that type of people, you know. We created it we're going, you know it's our responsibility.
NARRATOR: But the scientists who had seen the scale of the problems knew they had to get to the bottom of what was going wrong. They tested many theories. Perhaps clones made from adult cells were just dying from premature old age, perhaps cloning was causing strange mutations in their genes, but everything they looked at seemed normal. Many began to suspect that the problem lay in the great mystery at the heart of cloning: how could a single cell taken from an adult make a whole new animal, or human?
IAN WILMUT: We have a system which has evolved over millions of years to make fertilisation work, very effectively usually, and what we are asking it to do is something totally different, so really we shouldn't be surprised that it doesn't work very well. In a way almost we should be surprised that it does work sometimes.
NARRATOR: The way we are made is incredibly complex. Our genes are like the plates on a printing press. Each gene is a template that produces a message. To operate they need to be switched on and when they're switched on the different genes produce different messages that tell the cells how to build all the organs and tissues we need. To make a healthy human our genes need to be switched on at the right time in an intricate cascade and crucially when a process is complete they need to be switched off again, but the bizarre defects in cloned animals, like the massive blood vessels, suggested that something was going wrong with these critical instructions, so researchers began the quest to discover the problem. The first clue was to come from a scientist who wasn't doing cloning, but was working in a related area: IVF. For years scientists had been puzzled by the fact that some animals made by IVF for selective breeding grew dangerously large in the womb, something that also happens to clones. When Lorraine Young first set out to discover what was going wrong it seemed an impossible task.
LORRAINE YOUNG: To try and pinpoint what was going wrong was essentially a needle in a haystack type exercise. There are about 30,000 genes in every cell in, in an embryo and really any one of those could be going wrong.
NARRATOR: The answer to why the animals were growing too big could lie anywhere among 30,000 genes, but Dr Young knew of something which might help narrow the search. It was a rare disease in humans - Beckwith Wiedemann syndrome. Thelma was born with symptoms of Beckwith Wiedemann syndrome. It's a disease in which a vital few genes that control how we grow go wrong.
SUSAN CORDES: When Thelma was born she ended up being born with a part of her intestines formed outside of her stomach wall and she required surgery within one or two days of having been born.
NARRATOR: Beckwith Wiedemann syndrome causes dangerous errors in the way babies grow. They're often born very large with huge tongues and other problems that have to be corrected with surgery and cells in the liver and kidney can also grow out of control causing tumours. All this is caused by an error in the functioning of one of a small number of genes that control how babies grow. As a result, too much growth factor may be produced which in turn causes the tumours and abnormal growth. Thelma will have to have ultrasound scans every three months until she is eight to check for tumours.
HENRY CORDES: Well we try to go into these screenings very optimistic every time, but you never know if it's going to be OK until you, till the doctor, you know, takes his look and says it's OK and you try not to think about what it would be like if they came back and said it's not OK, that it means cancer, you know, and you don't want your child to go through that.
NARRATOR: Now Lorraine Young had a hunch that the same group of genes that caused problems in children like Thelma could also be making the IVF animals and clones grow too big. She began comparing the chemical signals coming from these genes in healthy lambs and overgrown lambs. It would take many months of painstaking work, but finally she found a crucial difference. One of the genes she was studying is meant to keep growth under control, but Dr Young found it wasn't producing strong enough signals and when she analysed it she found that something vital was missing. The switch that should turn the gene on, a tiny molecule called a methyl molecule wasn't where it should be. Without this switch the gene wouldn't work and the animal would grow out of control.
LORRAINE YOUNG: This observation shows that loss of these methyl groups from the DNA was enough to make the animals grow large and this was our most important result to date.
NARRATOR: Dr Young had done her work in IVF animals, but perhaps the same thing was going wrong in clones, perhaps the abnormalities were caused by switches like methyl molecules being disturbed. To test this theory scientists around the world began to look at tissue from clones to see whether metal molecules had gone awry. Like other scientists, Dr Zavos had also read about Lorraine Young's findings.
PANAYIOTIS ZAVOS: We're going to begin doing human reproductive cloning as early as probably 30-60 days from now.
NARRATOR: For him a problem found was as good as a problem solved. Horizon has tracked down a document in which Zavos claims he can actually make cloning safer by screening cloned embryos for the sort of errors Dr Young found and only using ones that look normal.
LORRAINE YOUNG: Frankly I think the claims are ludicrous and absolutely irresponsible. I find there's absolutely no scientific basis for them. It's poorly referenced and there's no real explanation of how he will do things. It just demonstrates a complete lack of scientific understanding in my opinion.
NARRATOR: Dr Zavos couldn't be interviewed by Horizon because he's tied in to a broadcasting contract elsewhere, but he claims that if the embryo has normal-looking methyl molecules on its growth genes he will assume it's healthy. He and Dr Antinori believe that tests like these will prevent many abnormalities.
SEVERINO ANTINORI: We will check and complete the procedure to monitor, to avoid 99% the abnormality.
NARRATOR: But Dr Young believes that the problem doesn't just affect the genes she's looked at, it could affect any gene.
LORRAINE YOUNG: There could easily still be problems in a whole range of other genes. He's going to be missing absolutely thousands of other problems. I mean he's going to be missing everything.
NARRATOR: In the last few months Dr Young's research has been backed up by other studies. Around the world scientists have published the first results showing that cloning sometimes causes vital methyl molecules to go awry on many genes. These results have led some scientists to a radical and devastating conclusion: that cloning can cause random errors in the switching of any one of 30,000 genes. The clone may develop normally until some key gene, like a time bomb, causes disaster and they believe human cloning would be just as risky.
IAN WILMUT: The most likely outcome would include late abortions, the birth of dead children and perhaps worst of all, the birth of children which survive but which were abnormal.
NARRATOR: And the risks don't end when we're born because as our bodies change at key stages in our lives we're dependent on genes switching on and off at the right time.
IAN WILMUT: Things can go wrong at any time. There are some genes which, for example, are necessary to make a child go through adolescence and not really important before then, so if you have an abnormality in that gene the child might not become a, a, a normal adolescent and you could see failures at, at any time of development. That I think is what we should anticipate if anybody clones a person with our present techniques.
NARRATOR: But there are other scientists who believe the case against cloning is hugely exaggerated and that these early problems will be quickly overcome.
GREG STOCK: To take those very early experiments which look at only a handful of genes and try to make some grand statement that cloning will never be feasible in humans or that it will be a very hard process or to make any assumption of that sort is unwarranted given the very preliminary nature of these studies.
NARRATOR: Dr Zavos and his team also think their opponents are exaggerating the risks.
PANAYIOTIS ZAVOS: Hello Dolly.
NARRATOR: He ridicules recent claims that Dolly herself may have something wrong with her brain.
PANAYIOTIS ZAVOS: Now Dolly was doing OK until recently when we heard the news and I was shocked Dolly does have an IQ problem. For crying out loud after four or five years old Dolly is, is stupid. Now for the life of me neither Oxford nor any other institution has developed an IQ test for sheep. Let's get serious ladies and gentlemen. You cannot do that. Of course I, I know about sheep because I was a sheep herder during my early life and I can tell you that I haven't met a sheep that is, has got an IQ above minus 10. Scare tactics are one thing, the facts of life are another and we need to stick with the facts. What is a clone? Mother Nature has its way of doing cloning. That is the identical twinning. The embryo splits and gives rise to two lovely children. A lady called me...
NARRATOR: Dr Zavos is right. Nature already creates thousands of completely normal clones every year, but recent research has revealed some remarkable cases of twins who are changing scientists' view of what will happen if humans are cloned.
RICHARD NACCARATO: Oh what a shot, that's right.
NARRATOR: Ricky and Erica are twins.
RICHARD NACCARATO: It's always special for every father to be in the delivery room for the first time. It was exciting, very exciting. She wanted a girl and I wanted a boy and we were happy, you know, like...
JOSIE NACCARATO: Very excited.
RICHARD NACCARATO: We had what we wanted and we had the millionaires family without the million dollars.
JOSIE NACCARATO: It was nice.
NARRATOR: Because they were different sexes everybody thought that the babies were non-identical, or fraternal twins, conceived when two separate eggs were fertilised by two separate sperm. They would be as alike, or unalike, as any brother and sister. This seemed to be confirmed when Ricky was born healthy, but Erica was not. She had some worrying symptoms. Suspecting a rare genetic illness, scientists did full genetic fingerprinting tests on both twins and what they discovered was astonishing.
JOSIE NACCARATO: They're identical twins.
RICHARD NACCARATO: I guess they are identical twins, but they're...
JOSIE NACCARATO: But they're boy and girl.
RICHARD NACCARATO: But they're boy and girl, so like you know the, what are the odds of having identical twins, boy and a girl - one in ten million? I don't know. You have to be a scientist to understand.
JOSIE NACCARATO: To understand that one.
NARRATOR: With Ricky and Erica, nature's intended clones had turned out to be very different, so what went wrong? The genetic tests revealed that the reason lay in their chromosomes. Ricky and Erica started off as a single, fertilised egg with an X and Y chromosome. With an X and Y this embryo should have become a boy, but as the first cells divided one cell lost its Y chromosome so some cells began to form which only had an X. Then the embryo split. One half had mostly XY cells - this became Ricky. The other half had only cells with just one X - this survived to become a baby girl, Erica, but it takes two X chromosomes to make a normal girl, so Erica is different. Girls with a missing X have a disease called Turner's syndrome. The twins are celebrating their eleventh birthday, but Erica is fortunate to have reached this age. She has had to have heart surgery and have her ovaries removed and as both twins approach adolescence the future looks uncertain.
RICHARD NACCARATO: This weekend she's 11 years old and it's creeping up on me and I think about it every day, the day I have to, you know, explain to her that she's not like every, every other little girl and when it comes to having a child she'll have to know that she's can't do it like everyone else has.
NARRATOR: Some scientists argue that if making clones naturally can result in unfortunate genetic diseases then man-made clones will be at much greater risk, but to others, making babies by any means is always going to be risky, so cloning is not exceptional.
GREG STOCK: The truth is that natural reproduction is a very, very dangerous procedure. We have abnormalities all the time. We have natural miscarriages and we have 3-4% of actual children that are born who have genetic abnormalities of one sort or another. We can't ask for absolute safety with cloning, but we can ask for a level of safety that is similar to those with other reproductive procedures.
ARCHIVE FILM NARRATOR: Within a few seconds of birth there was a huge, loud howl from Louise and the baby had arrived.
NARRATOR: 23 years ago a healthy baby girl called Louise overturned people's fears about interfering with reproduction. Louise was the first test-tube baby made by bringing sperm and egg together in a dish. Today IVF is routine and Doctors Zavos and Antinori claim that cloning will be just as safe.
INTERVIEWER: Whatever the consequences are you will go ahead with it?
PANAYIOTIS ZAVOS: There are not going to be any consequences. We think that we can, we can hit as high as IVF success which is about 30% in the US right now.
NARRATOR: But over the past decade a new form of IVF has emerged which is far more invasive. In a technique called ICSI weak sperm which could not penetrate an egg naturally are injected with a needle. Until human cloning is attempted ICSI is the only model we have to judge how human cells will stand up to the kinds of manipulations which cloning will involve. Although ICSI has produced thousands of healthy babies, a small number of scientists have begun to report problems. Several have linked ICSI to a higher risk of abnormalities. Some of the problems are likely to be inherited from the faulty sperm, but does the technique itself, which involves injecting DNA into the heart of an egg, cause problems? In the US one team decided to compare what happened to sperm and egg during the first few hours after normal fertilisation and after ICSI. They saw some worrying differences.
GERALD SCHATTEN: These are human sperm prior to fertilisation and you can see that they have this necktie like structure around the equator of the sperm chromosomes. (The chromosomes are in blue.) During fertilisation naturally, this necktie would be lost at the surface of the egg, but in contrast after ICSI here is a sperm in the egg and you can see that the red collar persists and that the sperm is not inflating uniformly as a round balloon but instead is constricted by that necktie.
NARRATOR: In nature a sperm's DNA would swell uniformly ready to combine with an egg's DNA, but after ICSI they found the sperm's packaging got in the way and the vital sex chromosome became trapped. The implications for cloning are serious because instead of injecting a sperm they'll use the nucleus of a completely different kind of cell that was never designed to meet an egg, so the potential for this kind of error is much greater.
GERALD SCHATTEN: Contrast that with cloning an animal like Dolly. Well first the mother's chromosomes are removed. We don't know what else is removed when the mother's chromosomes are removed. We don't wake the egg up by having a sperm wake the egg up. Frequently we use an electric zap. I mean is, is electrocution the best way to start off in life. It certainly isn't the method that's mirrored naturally.
NARRATOR: But still Doctors Zavos and Antinori claim they're on the brink of the experiment that will alter the course of human evolution.
PANAYIOTIS ZAVOS: Of course we're going to go ahead with it, no matter what. The infertility couples are the ones that make those decisions, not us, not them, nobody else. We are considering 200 couples. That doesn't mean that 200 couples will be cloned immediately. We will start with the first one and we'll finish with the two hundredth one.
NARRATOR: So could they actually succeed? Until they try it's impossible to tell, but other scientists have already tried to clone our close relatives - Rhesus monkeys. So far from more than a thousand attempts to clone a monkey from an adult cell, not a single one has succeeded. The DNA has so fragmented that no cloned embryo has yet survived, but some believe it's only a matter of time before these hurdles are overcome and that progress towards human cloning is inevitable.
GREG STOCK: First there will be a refinement of the technologies that are being applied to sheep and cattle and mice. There will be clonings that occur in dogs and cats and they will be reliable enough that actually people will be interested in cloning their own pets. There will be clonings that occur in Rhesus monkeys that will demonstrate these procedures are feasible in primates and at that point the risks will be sufficiently reduced that some group like the Zavoses and Antinoris of the world will leap in and attempt and actually succeed at doing a human cloning.
NARRATOR: And as the drive towards cloning continues more and more people are drawn to seek this new way to change their lives.
DESIRÉE RACQUER : I think I would say walk in our shoes. For one week walk in our shoes and then, and then judge, you know. Be, be in our situation and then judge us and I can guarantee you they will have a different judgement.
ROBERT WINSTON: The reason why I condemn you is for the same reason that virtually all responsible real scientists who publish real information condemn what you are doing and criticise what you're doing...
NARRATOR: For now, mainstream science, politicians and public opinion believe that cloning humans would be courting disaster.
ROBERT WINSTON: ...the reason why you should not be cloning is because it's dangerous, because it's unnecessary and because actually it is damaging our respect for human life and the dignity of human beings and you should be ashamed of what you are doing.
NARRATOR: But the momentum towards cloning may be unstoppable.
PANAYIOTIS ZAVOS: We either do it right, ladies and gentlemen, or we don't do it and those incidentally that wish to ban this technology, and I said this to the US Congress and I will say that to you tonight, they are not going to be the Neil Armstrongs that would fly, that would fly us to the Moon and walk us on it, therefore we need to be courageous, we need to move forward and we need to develop this technology in a safe, responsible fashion and I think it is the right thing to do and we intend to do that. Thank you.