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.

Medicine, which I wouldn't be without, has also been a force for... less good. For example, if you look at our mishandling of the immune system, using antibiotics in children and avoiding infection, we've certainly increased the risk of asthma.

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.

Over the past 20 years, I have presented many science programmes on BBC1. But none is, I think, more socially important, or of more human interest, than this ongoing series of 'Child of Our Time.'

I've been all over the world on my own because, as a scientist, you travel a great deal if your work is reasonably successful or published. I get invitations to go to all sorts of strange countries where I would mostly be by myself and just meet other people there, instead of having travelling companions.

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

To build and strengthen new connections, the brain needs the challenge of fresh and unusual stimuli. .... There's a lot of evidence to suggest that repetition is bad for brain health, and novelty is good.