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.

You can now modify the genes of large animals, and the largest animal we are concerned with is the human.

Ethics is not routinely taught to science students except in medicine, and I think it should be.

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.'

Man is a competitive creature, and the seeds of conflict are built deep into our genes. We fought each other on the savannah and only survived against great odds by organising ourselves into groups which would have had a common purpose, giving morale and fortitude.

I think it's important for scientists to be a bit less arrogant, a bit more humble, recognising we are capable of making mistakes and being fallacious - which is increasingly serious in a society where our work may have unpredictable consequences.

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.