Women of child-bearing age steadily run out of eggs by the continuous process of cell death. While reading a copy of the Guardian carefully from cover to cover, a normal woman will have lost on average two eggs - while, typically, a normal man will have made 70,000 new sperm.

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.

The trouble with climate change is it's an extraordinarily diverse and complex issue, but for example if the BBC would let me make some of the programmes I'd like to make on climate change, I bet you there would be a change of emphasis.

We must not fail to recognise that television can be a hugely positive influence in children's lives, one of the greatest educators in contemporary society and an increasing influence on all the children followed in 'Child of Our Time.'

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

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.

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.