Evolution’s Rainbow has now appeared in translation in Brazilian Portuguese and in Korean, and The Genial Gene in French. Also, a talented graphic artist, Gwen Seemel, has written and illustrated a lovely book that features many of the animal species discussed here and is suitable for children, titled Crime against Nature.4 I hope you join the many readers who have enjoyed and benefited from Evolution’s Rainbow.
Joan Roughgarden
Kapa’a, Hawai’i
April 17, 2013
NOTES
1. J. Roughgarden, 2009, The Genial Gene, University of California Press.
2. C. Darwin, 1871, The Descent of Man and Selection in Relation to Sex, John Murray.
3. D. M. Shuker, 2010, Sexual selection: Endless forms or tangled bank?, Anim. Behav. 79:E11-E17.
4. G. Seemel, 2012, Crime against Nature: A More Accurate Telling of What’s Natural, self-published.
Preface to the 2009 Edition
Evolution’s Rainbow surveyed the extensive diversity in sex, gender, and sexuality now known to exist among both nonhuman animals and people. When the book appeared in 2004, the extent of same-sex sexuality in animal societies was poorly publicized, even among biologists. Other phenomena such as gender multiplicity, sex-role reversal, and sex changes were even less well known. Biology undergraduates as well as the general public were being misled by textbooks and nature shows into thinking of a heterosexual binary as “nature’s way.” Today the situation has begun to improve; for example, exhibitions for the general public about gender and sexuality diversity opened in 2006 at the Natural History Museum of the University of Oslo, Norway, and in 2008 at the Museum of Sex, in New York City. Also in 2008, the Lesbian and Gay Veterinary Medical Association produced a DVD of my lecture at its 2007 annual conference in Washington, DC, titled Sexual Diversity in the Animal Kingdom, distributed through Amazon.com. Although it may be decades before information about the extent of sexual and gender diversity becomes common knowledge, the genie is out of the bottle at last.
The challenge today is to work through the implications of this diversity whose reality destabilizes our understanding of biological nature. The standard evolutionary account of gender and sexuality originates with Charles Darwin’s writing on the topic of “sexual selection” and these specific writings—not his overall theory of evolution—are challenged by the new information. I concluded in 2004 that the extent of this diversity pointed to sexual selection’s being on the wrong track. I proposed that Darwin’s theory of sexual selection should be replaced by a new theory that I christened “social selection.” Whereas sexual selection emphasizes mating, focusing on who mates with whom, social selection would emphasize participating in a social infrastructure to produce and raise offspring, and would focus more on how to deliver offspring into the next generation than on how to attract mates. In the social selection context, the diversity of gender and sexuality makes evolutionary sense, rather than seeming at odds with evolution, because of the valuable social roles the diversity represents.
In 2004, and probably even today, most biologists believe that Darwin’s original sexual selection theory can somehow be widened and extended to account for gender and sexuality diversity. I don’t think so. To the contrary, since 2004 the evidence and theoretical arguments against sexual selection have grown so much that those who continue to champion sexual selection theory are, I think, uninformed or in denial. Meanwhile, work on developing social selection into an alternative to sexual selection continues in my laboratory. This reissue of Evolution’s Rainbow accompanies the publication in 2009 of my new book, The Genial Gene, which extends my critique of sexual selection based on studies that appeared after 2004 and provides a summary of the research from my laboratory on social selection.
In addition to discussing diversity in gender and sexuality among animals, Evolution’s Rainbow, in the third of its three parts, reviewed gender and sexuality across cultures and through history. In particular, I called attention to passages in the Bible, in both the Christian and Hebrew Testaments, that teach the inclusion of gender-variant persons in community and worship. This theme has been taken up by religious scholars at Loyola University, Chicago, resulting in a book, Christianity, Gender, and Human Sexuality: An Interdisciplinary Dialogue, by Marie Vigen and Patricia Beattie Jung, to be published in 2009. Also since 2004, many advances have taken place in the public sector to secure rights for diverse people, although much remains to be done. Only in medicine and psychology, the areas treated in the middle part of the book, has the progress been disappointing since 2004. These professions are still dominated by binarist thinking that retards coming to grips with the facts of diversity.
I hope you enjoy this reissue of Evolution’s Rainbow. The book was exciting, even exhilarating, to write as I was uncovering fascinating information that I knew would be inherently interesting to many and would also challenge our preconceptions about what is biologically natural.
San Francisco
August 2008
INTRODUCTION
Diversity Denied
On a hot, sunny day in June of 1997, I attended my first gay pride parade, in San Francisco. The size of the crowd amazed me. As I marched from Civic Center up Market Street to San Francisco Bay, a throng of onlookers six persons deep on both sides shouted encouragement and support. For the first time, I felt the sheer magnitude of the gay community.
I stored this impression in the back of my mind. How, I wondered, does biology account for such a huge population that doesn’t match the template science teaches as normal? When scientific theory says something’s wrong with so many people, perhaps the theory is wrong, not the people.
It wasn’t just the number of gay people that astonished me, but the diversity of personal expression in the parade. A drag queen or two were featured in the newspapers, but many other, less flamboyant presentations with different mixtures of gendered symbols were evident as well. I was intrigued, and resolved to investigate further if I ever got the chance. During the next few months I intended to transition into a transgendered woman.1 I didn’t know what the future held—whether I’d be fired as a biology professor, whether I’d become a nightclub waitress, whether I’d even stay alive. I couldn’t make long-term plans.
Still, I found my mind leaping from one question to another: What’s the real story about diversity in gender and sexuality? How much diversity exists in other vertebrate species? How does diversity evolve in the animal kingdom? And how does diversity develop as individuals grow up: what role do genes, hormones, and brain cells play? And what about diversity in other cultures and historical periods, from biblical times to our own? Even more, I wondered where we might locate diversity in gender expression and sexual orientation within the overall framework of human diversity. Are these types of diversity as innocent as differences in height, weight, body proportion, and aptitude? Or does diversity in gender expression and sexuality merit special alarm and require careful treatment?
A few years after the 1997 parade, I was still alive and still employed. I had been forced to resign from my administrative responsibilities, but found myself with more time for research and writing. I was able to revisit the questions that had flooded my mind as I walked in the parade on that lovely day. This book is the result.
I found more diversity than I had ever dreamed existed. I’m an ecologist—diversity is my job—and yet I was still astonished. Much of this book presents the gee-whiz of vertebrate diversity: how animal families live, how animal societies are organized, how animals change sex, how animals have more than two genders, how species incorporate same-sex courtship, including sexual contact, as regular parts of their social systems. This diversity reveals the evolutionary stability and biological importance of expressions of gender and sexuality that go far beyond the traditional male/female or Mars/Venus binary. I also found that as we develop from tiny embryos to adults, our genes make decisions. Our glorious diversity is the result of our “gene committees” passing various biochemical resolutions. No gene is