In spring 2014, Ian Tucker, an editor at the Observer, asked me to write a story about menopause. That story opened me up to a huge wealth of research on women, and in particular the controversies inside the scientific community about how to define what a woman is. It was also the kernel for this book. I’d like to thank my editor Louise Haines at Fourth Estate for taking a punt on another book on sex and gender, and for her invaluable guidance and ideas. Thanks also to Amy Caldwell at Beacon Press, who came up with the title. My agents, Peter Tallack and Tisse Takagi, provided enormous help in shaping the idea in the first place and improving the manuscript when it was finished.
My heartfelt thanks also to the Society of Authors and the K Blundell Trust, which generously provided me with a research grant to allow me the time to write, buy books, and travel for research. Without their help, as a working mother I simply wouldn’t have been able to finish this. I hope their kindness to other writers in the same position as me never ends.
Many thanks to the Manuscripts Room at the Cambridge University Library for allowing me special access to Charles Darwin’s private correspondence, including his letters to and from Caroline Kennard of Brookline, Massachusetts. Also, thanks to the Wellcome Library in London for access to their archive collection of pharmaceutical advertisements. The UK Intersex Association and Intersex UK gave me help and advice on issues surrounding intersex conditions.
I am also grateful to a number of friends and academics for their assistance in proofreading certain chapters. They include Richard Quinton, Norman Fenton, Paul Matthews, Tom Vulliamy, Jahnavi Phalkey, Denise Sheer, Tim Power, Monica Niermann, Rainer Niermann, Rima Saini, and Mukul Devichand. Sarah Hrdy, Patricia Gowaty, and Robert Trivers were particularly generous with their time in answering my incessant questions. Dawn Starin was kind enough to offer her immense expertise in all my chapters on evolution. And Preeti Jha and Pramod Devichand read the whole thing with care and gave me invaluable feedback. But my deepest and most heartfelt thanks go to Peter Wrobel. I already thought he was the sharpest reader I knew, but his thoughts and fact checking of my manuscript have made me admire him more.
It’s impossible to write a book and raise a two-year-old without the help of a village. The people I must thank most are my mother-in-law, Neena, who took considerable time off from her job as a doctor every week to look after her grandson, and my wonderful husband, Mukul, who was willing to forgo my company and to care for our son alone in the evenings and weekends so I could write and travel.
I am grateful to all my family and friends, as I am to my much-loved son, Aneurin, for making me smile every time I looked up from my reading. I hope he will one day read this book, because I wrote it with his future in mind.