I don't believe in regretting - one should try to move on. My mum was good at that. She was deeply in love with my father, and he died when I was nine. She remarried, and her second husband died, too. I saw the grieving process she went through. My mother had this way of moving on. It was a fine trait.

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.

Although religion might be useful in developing a solid moral framework - and enforcing it - we can quite easily develop moral intuitions without relying on religion.

There were never any doctors in my family. But my grandparents and my mother had a strong social conscience that was formative.

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.

I do not know of any credible evidence that suggests Dr Zavos can clone a human being. This seems to be yet another one of his claims to get repeated publicity.

Childhood depression tends to be more common in inner cities, being most frequently related to serious social deprivation, bullying, domestic violence, wartime experience and famine. It is, for example, a serious problem among children who are traumatised refugees.