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

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'm a traditional Jew with an orthodox background, and it informs much of my approach to science. Of course I think it's very important that if you have those sorts of backgrounds you don't impose them on other people as a clinician, of course.

That Britain today is a liberal society is largely because of the philosophy and outlook of the Anglican Church, which did so much to shape our core values in the past few centuries.

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

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.

The disturbed individual who believes himself to be Christ, or to receive messages from God, is something of a cliche in our society. Ever since Sigmund Freud, many people have associated religiosity with neurosis and mental illness.