I don't believe the fertilised egg can be equated with the sort of human life that you and I represent, or our children represent.

However pragmatic you are, it is very demanding being a new parent.

Scientists need to be prepared to engage, and the best people to engage with are students, ideally from primary school because there's no question that their capacity to work out complex things is extremely good.

I don't know whether it is important to study science at a young age, though current thinking emphasises the need.

Both in Britain and America, huge publicity has been given to stem cells, particularly embryonic stem cells, and the potential they offer. Of course, the study of stem cells is one of the most exciting areas in biology, but I think it is unlikely that embryonic stem cells are likely to be useful in healthcare for a long time.

We live longer and healthier lives than ever before. Animal research has improved the treatment of infections, helped with immunisation, improved cancer treatment and had a big impact on managing heart disease, brain disorders, arthritis and transplantation.

I think it's important for scientists to be a bit less arrogant, a bit more humble, recognising we are capable of making mistakes and being fallacious - which is increasingly serious in a society where our work may have unpredictable consequences.