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.
People think I appear on television to promote my image. That's not fair. I hate filming. I turned down 'Strictly Come Dancing.' But television is a wonderful opportunity to promote scientific ideas. 'Super Doctors' is a very thoughtful piece.
Surgeons always underestimate the pain and disability involved in what they do to people.
IVF is very commercial. The people doing it are among the best-paid in medicine: they charge a lot per treatment and it's not in their interest to make it more effective. Having people fail means that they come back again.
Robots may cut down on infection and mean a consultant can see more patients, but wouldn't you rather meet the doctor than a machine?
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.
Much as I like and admire Richard Dawkins, I do think that to call a book 'The God Delusion' is very worrying because the title implies that if you don't believe in what I believe then you are 'deluded.' That, I think, is a dangerous concept and one that is unlikely to win hearts and minds.
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.
Animal rights activists talk about cruelty and torture, some backing their assertions by publishing out-of-date photographs of 'experiments' banned long ago. This is a misrepresentation. The work we do is performed with compassion, care, humanity and humility. I have never seen an animal suffer pain.
It is time my colleagues got real. All British universities doing worthwhile research use animals, and, instead of hiding, they should be boasting of their achievements.
Far too many scientists, including my good friend Richard Dawkins, present science as the truth and present it as factually correct. And actually, of course, that clearly isn't true.
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.
One of the most important aspects of what makes us who we are is neither straight genes or straight environment but actually what happens to us during development.
I think scientific arrogance really does give a great degree of distrust. I think people begin to think that scientists like to believe that they can run the universe.
Ethics is not routinely taught to science students except in medicine, and I think it should be.
I don't think you can impose limits on science because the very nature of homo sapiens is that he - she - is an inquisitive species. You can't control science. You have to control the effects of science.
Nearly all inventions are not recognised for their positive side either when they're made. So, for example, scientists didn't go out to design a CD machine: they designed a laser. But we got all sorts of things from a laser which we never remotely imagined, and we're still finding things for a laser to do.
Medicine, which I wouldn't be without, has also been a force for... less good. For example, if you look at our mishandling of the immune system, using antibiotics in children and avoiding infection, we've certainly increased the risk of asthma.
As parents, can we counter the effect of television violence? One worrying feature in Britain is that so many TV sets are in a child's bedroom; this means that the mediating effect of watching with a parent, the ability to discuss and interpret what has been seen, is lost.
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.'
