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.

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.

Having a child is arguably the most important thing you do in life.

When I look in the mirror, I am slightly reminded of self-portraits by Durer and by Rembrandt, because they both show a degree of introspection. I see some element of disappointment; I see a sense of humour, but also something that is faintly ridiculous; and I see somebody who is frightened of being found out and thought lightweight.

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.

While nobody has identified any gene for religion, there are certainly some candidate genes that may influence human personality and confer a tendency to religious feelings. Some of the genes likely to be involved are those which control levels of different chemicals called neurotransmitters in the brain.

My own field, the prevention of genetic disorders in babies, has been possible only because of humane work on animals.