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.

My own field, the prevention of genetic disorders in babies, has been possible only because of humane work on animals.

I like travelling on my own. It means I'm completely free to think about what's around me.

It is important that legislation keeps pace with scientific progress.

We can't any longer have the conventional understanding of genetics which everybody peddles because it is increasingly obvious that epigenetics - actually things which influence the genome's function - are much more important than we realised.

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.

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.