Of course it is a very simple matter to identify genes which might modify intelligence or memory and start thinking about whether you want to enhance a human, and the next generation is going to have to deal with that issue. Should we be trying to enhance humans rather than trying to educate them and so on?

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.

A young woman in her teens has about 300,000 eggs in her ovaries. By the time she is menopausal, none are left.

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 don't know whether it is important to study science at a young age, though current thinking emphasises the need.

It's extraordinary to think that if you walked into a room and said you had never heard of Hamlet, you would be regarded as a Philistine. But you could walk into the same room and say, 'I don't know what a proton is,' and people would just laugh and say, 'Why should you know?'

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.