Let me describe to you how we produce the cloned sheep. You can see the big cell here is an egg which was taken from a sheep at the time when usually she would have been mated. And that pipette has been pushed into the egg in order to remove the chromosomes, carrying all of the genetic information from that egg. Because what we want to do is to use that pipette to pick up the second cell - which in the case of Dolly came from mammary tissue of a different sheep - and introduce the genetic information from that cell into the egg, so that we get a sheep which is genetically identical to that original one. And you can see that the cell that we use for that is much smaller than the egg cells - egg cells are the biggest cells that mammals have. It's been picked up in the pipette there, and it's now going to be pushed, the pipette's going to be pushed through that shell, so that the cell can be deposited in that space.

Even though the egg is extremely large, I should tell you that it's only a tenth of a millimetre in diameter. So you can only just see them with the naked eye, and all of this is being done on a microscope. So the pipette now is going to be used to push those two cells together, so that in a few moments we could use an electric current to do two things. It can fuse those two cells together; and it can activate that egg, it can stimulate it to begin development. And what would happen in a few hours is that that single cell would divide into two cells, into four cells; we'd choose the eggs which were developing normally; and then we would transfer those into foster ewes in order to give them the chance to develop into lambs. This is a webcam for the Institute where I work near Edinburgh, showing you some of the cloned sheep that we've produced with our neighbours PPL Therapeutics.

That's great - so it's coming direct over the Internet to us from Roslin now?

So clearly this is a technique which does work, it does produce some cloned animals that are perfectly healthy. But it's a very inefficient process; so that overall only about one in a hundred of the eggs that we produce survive to become live offspring, because there is a death of embryos, and then of foetuses, throughout pregnancy.

So that would mean that the idea of using the same technique for cloning humans would be really...

It's distressing enough.

When this happens with animal ... but it's surely inconceivable that people would think of doing it to copy a person at the present time. Because we see a great variety of different abnormalities. We had a lamb born at Roslin almost a year ago which was very big and strong, it ate a lot, ran about, was very healthy, except that it panted all of the time, night and day. We took advice from medical doctors, veterinary doctors, tried all of the treatments, but unfortunately none of them was effective. And in the end we decided it was kinder to kill the lamb, when we were able to look at lung tissue. And on the left-hand side you can see lung tissue from a normal lamb; and on the right hand side tissue from this lamb. And you can see the big circle of red tissue is musculature around one of the blood vessels in her lungs. And the reason she had a problem is that that vessel was so constricted that not enough blood could get to the lungs to pick up oxygen to circulate round the rest of the body.

So it's because of the complexity of making a mammal like us that such a small change is dreadful.

It really has catastrophic effects, yes.

So it would be, you do believe that it would be a bad idea to risk producing defective human beings of this kind, but then there's the further thing how would it actually feel to be a human clone, I guess.

I think this is the question that we have to ask ourselves. If one day the technique is safe, should it be used to produce clones? What would it be like to be genetically identical to our parents? The clone would be more similar to the parent than any other child except an identical twin born at the same time. Just exactly how would it feel?

Well here's Joe.

Joe is the young man's name, I believe. Is he in the audience? Can he come down?

Yes Joe, do you want to come down? Here he is, good. (APPLAUSE) Stand here - show us yourself - well done.

Joe we're going to show you what you're going to look like in forty years time, we're going to age you. I don't know how similar you are to your own father, but - you could look at your hair receding - and believe me it happens at an astonishing rate (LAUGHTER). So, we can ask Joe a rather unfair question - how would you like to be like your father?

Not very much. (LAUGHTER)

And we can ask parents who are viewing: do they think that it would be possible for them to treat a child who was like them in exactly the same way that they would treat a child produced normally? I think - I have children of my own, and grandchildren - I think there would be a tendency to say "it's okay son, don't try that; I tried it a long time ago and it's not very much fun." Or alternatively to encourage people, and expect them to do particular things. So the relationship would be different.

Thank you very much Joe. That was a difficult question. (APPLAUSE)

So that's the issue of human cloning, and I think there's a lot of things to think about there - we'll come back to it at the end, in fact - but really the reason you've done this work, Ian, is not for that at all, it's for useful purposes, isn't it?

There are at least two uses of cloning that I'd like to describe for you. The first is to try to produce cells to treat, to be able to treat, some very unpleasant human diseases - diseases that are caused by damage to cells that are not repaired or replaced. And you can think for example of Christopher Reeve, who I think we will all know had a tragic accident when he was riding, has damage to his spinal cord, and so is seriously paralysed. And there is no treatment for that. Another disease is Parkinson's Disease - Michael J. Fox has that - and you know some of the symptoms that are caused by that disease. There is no effective treatment. Now one possibility would be to take a cell, a healthy cell, from these men, to clone to produce an embryo, and then to grow from that embryo cells of the type that were needed to treat the disease. So you could choose spinal cord nerves for Christopher Reeve, for example. Because the cell that we used to clone was from the patient, the cells that we would create would be immunologically like the patient, so you could put them straight into the patient without any fear of rejection. And one day it maybe possible to use this technique to offer treatments in that way. The second is actually concerns the sheep that we have at Roslin, because these are actually genetically modified. It's a surprise when you first think about it, but in fact we can make precise changes in the cell that we use to give the genetic information, so that when the animals are produced they're genetically different. And in the experiment we did with our neighbours, we introduced a change in these sheep so that they produced in their milk the protein clotting factor nine, which is missing from people who have haemophilia. And they, the company can extract the protein from the milk, and prepare it in a pure way, so that it can be given to patients with this sort of disease. And I think these are two potential uses of the cloning technology, which I personally would support.

And that's what it's really all about.

Ian, thanks very much indeed for being with us.

Now there were one or two questions arising there. One is, taking up Ian's last point, in terms of humans - do you think that it's a good idea to clone human beings simply as embryos for to produce stem cells that will allow them to be cured of bad diseases - do you think that's a good thing to do, or not? Green for good; red for bad. How do you feel? Because you are the people who are going to have to make these decisions in the future you know. It's not for us old guys - you're going to be the parents, the doctors, the politicians, who are going to have to discuss these things. And I can see there's quite a mixture of opinion, but this particular one it's got a clear preponderance of yes. Put them down again now, and now another question. How would you feel about the morality of cloning in the same way if it were reasonably safe - Ian's emphasised the difficulties; so let's forget about the technicalities - but how would you feel about cloning to produce a new human being? And you're really not very comfortable with that at all are you. But why are you not comfortable? There's a guy there on the end just by you who said red. Do you want to say why you're voting against?

Well to make, like, another human - it's kind of wrong if you think about it, in my opinion, because they should really have a chance in life to, if they're born of their mother just normally, then they should have a chance that… it's fair just to give them a chance of just having a life, live their own life actually ...

So they should live their own life. Is that what you're saying?

Can you pop your cards up again and see who voted - is there anybody there who's voting green - yeah?

Because if humans get cloned they can never die.

I'm glad you said that, but I'm going to disagree with you a tiny bit - okay? - let me explain. These identical twins, okay, are not the same people, right - I'm sure they'd all agree to that. They're very, very alike, but you're not the same person, you're your own person. Do you see what I mean? And so it's certainly - I think that it's often felt that if somebody clones themselves they would actually be carrying themselves on, but you won't. You see, you produce an identical twin who will have their own ideas, their own experiences, and their own thoughts. And in fact they'll be more different from the parent than these twins, because they'll be in another generation. That's what Ian was emphasising, you see. You'll be younger - you'll have lots of different experiences; so that if an adult like me decides to clone himself, there's no guarantee at all - in fact almost a negative expectation - that the clone would turn out like me. Okay, well thank you very much, it's extremely interesting to see your opinions. And now what we've seen throughout all of this is that we have strong effects of genetics; that it's not unreasonable that genetics influence us in all sorts of subtle ways; and also though, as we see with our twins turning out to be different people, in some cases quite different to one another, the nurture you have, and the parenting you have, is enormously important. So I think the thing to think to oneself is that I am more than a sum of my genes - I think that's really important. And so that's human variation, and next time we're going to think about how all these new ideas, the information the knowledge we're acquiring, can help us to cure disease. (APPLAUSE)