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.

I don't much like being a public figure, because so often how people appear is not how they really are, and I think one of the issues about our society is that we make judgments about people on the basis of very flimsy evidence.

In prehistoric times, Homo sapiens was deeply endangered. Early humans were less fleet of foot, with fewer natural weapons and less well-honed senses than all the predators that threatened them. Moreover, they were hampered in their movements by the need to protect their uniquely immature young - juicy meals for any hungry beast.

Scientists need to be prepared to engage, and the best people to engage with are students, ideally from primary school because there's no question that their capacity to work out complex things is extremely good.

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

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.

I went to school with butterflies of fear every day for years - from primary school onwards - not just worried about being bullied by classmates, but by teachers.