Prof. Gregory Stock: "Certainly they're choosing their babies' genes in the way that people have always chosen their babies' genes, and that is by the choices they make in their mates. This is a very powerful selective tool that is geared by such things as attractiveness, health, even indirect expressions - aspects of our genetics like ability or leadership - but at this point it's a different story to be making explicit choices about the genetics of our children."

Chris Rigby: "Surely only physical characteristics can be genetically programmed? No personality or mental features can?"

Prof. Gregory Stock: "We know that aspects of our personality and behaviour are also strongly influenced by our genetics. So it stands to reason that as we unravel human genetics and the way it influences us, both physically and mentally, that there will be some things that are relatively simple and straightforward to manipulate."

Cathy Weston: "How close do you think we are to realistically being able to choose the characteristics of our offspring? And can you ever see it being legalised?"

Prof. Gregory Stock: "It depends on the degree of choice that we are talking about. Already we can make choices about the gender of a child. We can do PGD (Pre-implantation Genetic Diagnosis) to avoid certain diseases like cystic fibrosis. As the human genome is deciphered and understood, there are likely to be many things that are too complicated to manipulate or select. There are likely to be some traits that are difficult to manipulate and there are likely to be some that are astonishingly easy. Which will fall into those different categories is unclear at this time. But we will likely know within another decade. And to do genetic selection is extremely close. We already do it in simple ways, and those possibilities will expand very rapidly in the next decade - especially as gene chip technology is improved so that tests are cheap and easy."

Joe Smithe: "What exactly is PGD and how does it work?"

Prof. Gregory Stock: "Pre-implantation genetic diagnosis - PGD - is the process by which a cell from a four-to-eight-cell embryo is removed and genetically tested. This does not destroy the embryo. Based upon the results of this test, a decision can be made by a parent or parents as to whether to implant that embryo or not. So it is an adjunct to in vitro fertilization - which is of course commonplace."

Piers Johnson: "How close are we to making an artificial human chromosome?"

Prof. Gregory Stock: "Human artificial chromosomes have already been made by a group at the University of Pennsylvania and by a company called Chromos in Vancouver, Canada. They are stable for many generations in human tissue culture. In mice, an artificial chromosome has actually already been passed reproductively."

Carmen Diego: "If an artificial chromosome is added to a foetus, will it be able to have children naturally when it is an adult?"

Prof. Gregory Stock: "The artificial chromosome would be added to the first cell in an embryo and then would be copied into every cell in the body of the ensuing adult. A person would be able to reproduce but they would undoubtedly not want to pass the artificial chromosome to their children because technology would have advanced by a generation by that time."

BBC Host: "If an artificial chromosome is added to an embryo, that person will have 47 chromosomes. Could that person mate with a "normal person" with 46 chromosomes?"

Prof. Gregory Stock: "To overcome the difficulty of not having matching numbers of chromosomes, schemes to use artificial chromosomes involve deleting that chromosome at the time of reproduction and replacing it in the new embryo. This could be done automatically through some technical tricks. But clearly, you begin to enter the realm of obligatory assisted reproduction."

Astrid McCrory: "Do you think that PGD may eventually replace IVF?"

Prof. Gregory Stock: "PGD is an adjunct to IVF. It will likely become extremely commonplace, and I believe it will be used in virtually all in vitro fertilization attempts. And in fact, it may very well be possible to project a "virtual" child that would result from a tested embryo, and parents could select their offspring on that basis."

Mirsa Karjallanen: "Do you think that, in the future, reproductive technologies will be driven by market demand?"

Prof. Gregory Stock: "Yes. I think that the primary force behind the new reproductive technologies emerging will be the desire of parents to do the best that they can for their children, using genetic means just as they today use special educational tools and other efforts to give their children advantages."

Astrid McCrory: "Do you think that public awareness would be enough to stop people from wanting designer babies?"

Prof. Gregory Stock: "No. I believe that the technologies will be so easy that they will be almost impossible to block. If the technology were illegal in Britain and a couple went for a romantic holiday to Bermuda from which they return and have a child - is the government going to do a genetic test on the child to determine whether it is completely "natural"? They could not possibly determine if genetic selection had occurred, and even if they could, whom would they punish?"

Astrid McCrory: " If in the future cloning becomes commonplace, then would this not have some effect on the gene-pool, as in, there would be a lack of variety and this could lead to the fall of the human race?"

Prof. Gregory Stock: "The human gene pool is immense, and any cloning would have negligible impact. The effects on the human gene-pool occurring today are substantial, but they primarily come from modern medicine allowing those who would otherwise die from childhood diseases to live and reproduce, and clearly we would not want to stop that intervention. Changes to the gene-pool caused by advanced reproductive technologies are simply not a real issue."

Andrew Child: "Do you not think that designer babies may be something which could be paid for by the NHS, and therefore extend to the many, if the intention is to prevent disease? It may make economic sense."

Prof. Gregory Stock: "I think that as human enhancements become possible through advanced reproductive technology, that there will be enormous pressures to make them available to everyone. In an egalitarian society where there is no way to block the use of these technologies by those who are committed to doing so and have resources, others will want access as well."

Horza: "If two males wanted to create a child using their own genetic material would the resulting offspring always be male?"

Prof. Gregory Stock: "The ways that exist today for a male couple to have a child that has a genetic contribution from each, would be for each to use IVF with a female donor and then combine the two embryos."

kim: "Technology has positive connotations - people believe in its promise. Do you think that in the future when people can design their own babies, those who refuse it will be accused of not giving their offspring the best possible care?"

Prof. Gregory Stock: "I think that when we have the ability to intervene in this realm, there will be a whole new area of law - issues such as wrongful birth, where children sue their parents for not correcting some disease, and others who sue their parents for "improvements" that were made. But my perspective is from the United States, where everyone sues everyone!"

Jo Burley: "With the development of genetically improved immunity and overall longevity, what is the likelihood of a virus mutating to overcome the genetic improvements in human beings. If this is a possibility then surely a virus that can make a 'super-human' ill will annihilate the remaining humans with unaltered genetics."

Prof. Gregory Stock: "I think that future humans will be susceptible to viral infection, whether enhanced or not, but there is no reason to think that something that would affect an enhanced individual would therefore devastate an un-enhanced one. I think that as with any powerful technology, there will be abuses of it as well as enormous benefits. In this case, I think that the benefits are likely to far outweigh the negative consequences. But one could imagine, for example, parents trying to create more obedient children or more religious children. There have already been individuals within the deaf community who would like to choose to have a deaf child."

Simon Harding: "Presumably patenting artificial chromosomes will be possible?"

Prof. Gregory Stock: "Several different types of artificial chromosome have been patented already, and it is feared that there will be a host of patents on the technological platforms for these types of interventions. But patents are the way that this kind of technology is commercialized and developed. This is entirely different from the idea of ownership of a future human, which will never occur."

BBC Host: "Have single genes been patented? Is this ethical?"

Prof. Gregory Stock: "The answer is yes. But we must remember that patenting is not ownership. It is the right to block others from commercial use of a particular intervention for a limited period of time. So the moral issue of ownership is really a red herring."

Anna: "Do you think that there is a substantial risk to carrying out germ-line therapy on human beings at the stage science is at now, and do you think there will be a time when there is no risk for a baby who has been genetically manipulated or designed?"

Prof. Gregory Stock: "Yes, there is a substantial risk now - so much so, that no responsible physician would attempt such a thing on a human embryo. But it is very likely that these technologies will become relatively safe in the not too distant future. I speak of relative safety because we must remember that natural conception is an extremely dangerous process. Seventy-five per cent of embryos never make it to term."

Gerard Klauner: "Currently, we can hardly criticize our parents for what we are, but can you imagine the psychological problems when a child realizes his parents had a choice?"

Prof. Gregory Stock: "Sometimes children do criticize their parents for who they are or the opportunities that they received or the chances that they were given. When these criticisms enter the genetic realm, they may be very difficult in some cases, but to say that they are so significant that we should not do these sorts of things would be a projection made with no evidence whatsoever. Things will be very strange and different in the future and who knows how we will view them."

Jo Burley: " Nature has a way of balancing the scales. Don't you think we're pushing it a little too far?"

Prof. Gregory Stock: "You could say that about all of human civilization. What is going on today in virtually every realm is without precedent in the history not only of humans but of all life. We are moving out into space, where life has never before gone. We are breathing a complexity into sand and minerals through the modern computer that rivals that of life itself. And now we are seizing control of our own evolution. I believe that when future humans look back on this era they will see it as a difficult, turbulent moment that laid down the very foundations of their lives."

Liz: "Do you think that creating designer babies will lead to discrimination and even a new form of racism between those who have been altered and those who have not?"

Prof. Gregory Stock: "I think that it will lead to many challenging social issues, one of which will be simply the gulf between generations as the technology becomes more and more powerful. I think that discrimination against those individuals who have used the technology will be unlikely because it will not be obvious visually as is our ethnicity and race."

Tina Ferrari: "Please can you tell me where I can find more info on PGD and if it is available in the UK?"

Prof. Gregory Stock: "I believe PGD was first used in the UK for cystic fibrosis in 1990. I think that the Horizon website has links to further information on the subject. For more information on germ-line genetic engineering you can also visit the UCLA website (http://research.mednet.ucla.edu/pmts/germline). I would like to add that it is genetic manipulation and enhancement that will be the real ethical challenge for us, because it will bring into question the very nature of what it means to be human."

BBC Host: "It is currently illegal in the UK to use PGD to test for genes other than those associated with certain severe or life-threatening disorders."

Liz: " What do you see coming next in this new technology?"

Prof. Gregory Stock: "I think that the thing that would most impact our lives would be extensions to the human life-span. I think it quite plausible that as we unravel the human genome and the process of ageing, we will be able to manipulate and retard it. Doubling the human life-span would change virtually everything about human society and the way we see ourselves, and about the trajectory of human life. This is the magnitude of change that we will be facing in the next few generations."

"Personally, I find it a great privilege to be alive at a moment when human life is being so dramatically transformed."

Read Prof. Gregory Stock's article "Humans: Objects of Conscious Design".

Horizon: Designer Babies programme page.

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