Here she dreamcasts a film based on her new book, Darwin and Women: A Selection of Letters:
It's odd you should ask about who would play my characters -- or really, correspondents -- in a film, as I've always had a strong idea that my Emma Darwin would be Kathy Bates. She has exactly that mix of shrewdness, practicality, and serenity that I associate with Emma. There aren't many images of Emma in circulation and most people probably have only seen the watercolour of her as a very pretty young girl. In her letters she's intelligent (she was particularly interested in politics), funny, and has sometimes has an extremely sharp tongue.Learn more about Darwin and Women at the Cambridge University Press website.
I'm always stumped by who would play Charles Darwin though. Paul Bettany did a fine job in the film Creation, but somehow I feel that there's still room for another Darwin. Benedict Cumberbatch, however, may have been a definitive J. D. Hooker: he was a man with a great deal of character, some of it not pleasant, but always compelling!
For Henrietta Darwin, you'd need someone intense to the point of being slightly alarming: possibly Nicole Kidman or Marianne Moore? And for Elizabeth Darwin, Darwin's other daughter, someone who could be a little self-contained and aloof: Anna Maxwell Martin would be perfect.