I turned 65 last year, and each year I get more and more interested in human health. For most people it happens around age 50, but I've always been a slow learner. It's critical in terms of the cost of health care.

I've had a very unusual background in science - not the usual route of planning on being a scientist from age 3. I think my story shows that success is more about personal motivation and determination than it is about where you were born or what your economic status was.

In the past, geneticists have looked at so-called disease genes, but a lot of people have changes in their genes and don't get these diseases. There have to be other parts of physiology and genetics that compensate.

My early years were hardly a model of focus, discipline, and direction. No one who met me as a teenager could have imagined my going into research and making important discoveries. No one could have predicted the arc of my career.

For me, it's just acting. It's pretending. The best actors are children, and children don't do research. You never see a child going, 'I'm wondering about my motivation here. How can I do this toy? How can I do this train? I don't feel train.'

I was always a reformer. My father and mother were progressives, and they believed in the universal vote, vote for women, land reform, and a lot of things which at one time were not accepted; they're much more accepted now.

As my father taught me, and he drove home that point, he said, 'Just remember something. You don't need to tell anybody how good you are. You show them how good you are.' And he drove that home with me. So I learned early not to brag about how good I was or what I could do but let my game take that away and show them that I could play well enough.

I would say that the things that have really left a mark on me have more to do with my family and my children's lives rather than a film role.