'All we are doing is trying to help someone who is sick. I believe we have an obligation'

Mohammed Taranissi, director of the Assisted Reproduction and Gynaecology Unit, London.

"Any family could find themselves in the same situation as the Whitakers. We made an assessment and, in their case, we decided there was no reason why we should not help them.

Talk of designer babies and spare part babies is wrong - we have no ability to design babies. All we can do is screen for certain conditions, and those are not trivial issues such as the colour of eyes or hair. We can't change anything. We are not playing God. What we are doing is no different from what we have been doing in IVF for 25 years; selecting the best embryos to place in the womb. If people have a moral issue about this they have a moral issue about IVF as a whole.

Suzy Leather [who chairs the Human Fertilisation and Embryology Authority] said the Whitaker case was different from the Hashmi case, because, in the Hashmi case, the embryos are being screened for thalassaemia as well as being tissue typed to ensure they are a match for their son Zain. But if they find a genetically normal embryo that is not a match, they are not going to use it. Is this ethical? Tissue typing is either right or not. Doing something else with it does not make it more right. It is more unethical to create a normal embryo and then not use it because it is not a match.

Would I treat a family where it was not the sibling that needed help from the new baby but the father? That is a completely different situation. I really don't know the answer. The principle is the same - you are trying to help someone who is sick.

I can't tell you straight away. You might find an exact match in a baby that was naturally conceived. What then? I just believe we have an obligation to help treat illness and that this is one way of doing it.

There is a big fallacy children should not be created with some ulterior motive in mind. All the time children are created for a reason - to complete the family, to provide a sibling for an existing child, to keep a couple together. What we are doing here is no different."

'This child does not have the right to its own birth ... The fact is that this is eugenics'

Josephine Quintavalle, anti-abortion campaigner and director of comment on 'Reproductive Ethics'

"We always say we don't know what we would do in desperate circumstances, but that is not the way to settle what is right for society at large.

Right from the start, this child did not have the right to its own birth. The parents' thoughts were not on the birth of the child. And it lives under the threat that it might be asked for future donations.

You are looking at an unwilling victim that is being manipulated by its parents. At one stage, the child is hosted in its mother's womb but it is not something you own. I am horrified at the idea that we have rights over our children and can dispose of their tissue as we choose.

You have to look past the issue that it would just be the cord blood that would be used. There is an ominous suggestion that the Caesarean may have been performed on Michelle Whitaker not, as reported, because this was a breech baby, but to maximise the amount of cord blood.

The other issue is that if you don't get the tissue match, you throw all the embryos away. How many times would you do that? Is it appropriate to look for cures for disease in this incredibly wasteful way?

The distinction made between this case and that of the Hashmis is a perversion on the part of the Human Fertilisation and Embryology Authority. The real question is: is it ever right to select a baby in this way? What the HFEA is saying is if you are weeding out defective embryos, you can look for the positive qualities you want at the same time.

In fact, what happens is that first you look at the embryos and select the healthy ones and then you look at the healthy ones and see if they match [the sibling you want to help] and if none of them match you dispose of them.

I don't think you can get away from the fact that this is eugenics. We should be looking for a solution to the disease rather than creating another child to solve the problem."

Jeremy Laurance