I think that good parenting should allow children to be children. That naivety and slightly open way of looking at the world is very valuable.

Childhood is not dead. Children were worse off when we were hunter-gatherers; they were threatened in medieval times and exploited during the Industrial Revolution. Was it any better in the time of Charles Kingsley or Charles Dickens?

Carbon dioxide is unusual because it doesn't go through the usual three phases of matter, from solid to liquid to gas, but it goes straight from solid to gas. The volume of the gas is much greater than the volume of the solid. When a solid turns into a gas, we say it sublimes. The process is sublimation.

Our aggression is a deep instinct which survives in all kinds of manifestations in modern man.

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.

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 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.