The UCLA Center for Society and Genetics
Third Annual Symposium:
Gender and Genomics: Sex, Science and Society
January 30, 2005
Grand Horizon Room, Sunset Conference Center
Co-Sponsors: Charles R. Williams Project on Sexual Orientation Law and Public Policy – UCLA School of Law; and the UCLA Center for the Study of Women
Are we born male or female? Will men one day be extinct?
How do we choose our mates? Is gender divided into feminine or masculine, or is it somewhere in between? Research in biology, history, psychology and beyond is challenging our everyday assumptions about our sexuality, our sex and gender roles and our identities.
UCLA’s Center for Society and Genetics third annual symposium, Gender and Genomics: Sex, Science and Society, offers insight into the complexity of sex and gender while reflecting on the cultural and historical forces that shape our sexual behaviors, attitudes, and self-understandings.
Speakers and Topics
Alice Eagly, Ph.D. Northwestern University
On the Flexibility of Human Mating Preferences:
A Social Role Analysis
Alice Eagly is a professor of psychology at Northwestern University. Earlier she served on the faculties of Purdue University, University of Massachusetts in Amherst, and Michigan State Universities. Eagly earned her doctoral degree in social psychology from the University of Michigan and her bachelor’s degree from Harvard University.
Eagly has published widely on the psychology of attitudes, especially attitude change and attitude structure. She is equally devoted to the study of gender. In both of these areas, she has carried out primary research and meta-analyses of research literature. She is the author of Sex Differences in Social Behavior: A Social Role Interpretation and The Psychology of Attitudes and the co-editor of four volumes. Eagly is also the author of numerous journal articles, chapters, notes, and reviews in her research specialties.
She has served as President of the Midwestern Psychological Association, President of the Society of Personality and Social Psychology, Chair of the Executive Committee of the Society of Experimental Social Psychology, and Chair of the Board of Scientific Affairs of the American Psychological Association. She has received several awards, including the Distinguished Scientist Award of the Society for Experimental Social Psychology, the Donald Campbell Award for Distinguished Contribution to Social Psychology, the Gordon Allport Award of the Society for the Psychological Study of Social Issues, and the Citation as Distinguished Leader for Women in Psychology from the American Psychological Association.
Human mating preferences and sex differences in these preferences are quite varied and flexible because they reflect people’s learning of the likely consequences of their choices of mates and the sharing of that learning within cultures. These observed consequences of mate choices are organized to a great extent by the social roles of men and women, especially by marital and gender roles.
Social roles shape the observed relations between potential partners’ attributes and important life outcomes and therefore influence preferences for partners.
Jennifer A. Marshall Graves , Ph.D. Australian National University
Professor Jenny Graves’ work on Australian mammals provides a unique view on the way that the human genome evolved and how it works. Geneticists use variation to test the influence of genes on characteristics – she has capitalized on the very distant relationship between humans, kangaroos and platypus to provide enough variation to study even very fundamental genetic processes, like sex and embryonic development.
One of her group’s big successes was in her research on sex and sex chromosomes. It was their work on kangaroos that first showed that the prevailing hot favorite candidate for the sex determining factor was the wrong gene, and it was her PhD graduate who then went on to clone the right gene (SRY) in London. SRY is on the Y chromosome, which is present only in males. The Y is a very odd chromosome – it is small, and largely made of junk. Professor Graves’ group discovered from comparisons across species that the Y is just a broken down X chromosome. It has lost most of its original 1000-odd genes at such a rate that Jenny Graves predicts that the Y will disappear in another 10 million years or so, as has already happened in some weird rodents.
Most recently, Jenny Graves has lead the effort to see that the genomes of the kangaroo and the platypus are sequenced, marshalling resources in Australia and overseas and building Australian teams and international collaborations. The genomes of these unique animals are treasure troves full of unknown genes, and information on how they work. Being able to compare sequences in and around he same genes in humans and kangaroos can identify new human genes and the signals that switch them on and off, and can also lead to the discovery of genes that control marsupial-specific characteristics that might be handy for agriculture and medicine.
In humans, as in other mammals, females have two X chromosomes, and males a single X and a Y. The presence of a Y chromosome is male determining because it bears a gene (SRY) that switches on testis development. The embryonic testis pumps out hormones that determine maleness.
The X chromosome is a very decent, ordinary sort of chromosome, although it seems to have more than its fair share of genes that are involved in male sex and reproduction – and maybe sexual behavior and intelligence. But the Y is a genetic wasteland – small and full of genetic junk, bearing only 45 genes. Most of these genes are active only in the testis and have functions in making sperm.
We know that the X and Y evolved from an ordinary pair of chromosomes as the Y was progressively degraded. To explore the origin of the human Y and SRY, we compared Y chromosomes of the three major mammal groups (eutherians, marsupials and monotremes), as well as their predecessors in birds and reptiles. This showed that human sex chromosomes evolved quite recently, but has links to ancient bird/reptile sex chromosomes. Comparing sex chromosomes of distantly related mammals allowed us to subdivide the human Y into a tiny ancient region and a recently added region. Most of the original human Y has been lost, and the Y was saved from extinction only by adding bits from another chromosome, which are also being degraded very rapidly.
The Y chromosome is therefore a degraded relic of the X. We find that most genes on the human Y – even those with important functions in male determination and differentiation – have partners on the X from which they evolved. The sex-determining gene SRY evidently evolved from its partner on the X (the brain-expressed SOX3), leading to many questions about how a brain-determining gene could take on a new role as a testis-determining gene.
The human Y chromosome is running out of time. At the rate it is degrading, it will lose its last 45 genes in just 10 million years. What will happen when SRY is lost? We cannot go in for a female-only lifestyle (called parthenogenesis) because many vital “imprinted” genes are active only if they are derived from the father. Since we can’t reproduce without males, would this be the end of the line for our species? The good news is that SRY has been lost in at least two groups of rodents. Somewhere else in the genome, a new sex determining gene must have taken over the function of SRY.
Professor Graves predict that as the human Y runs out of options, new sex determining genes will evolve. If different new sex determining genes arose in different human populations, they could ultimately become different hominid species.
Joan Roughgarden spent her early childhood in the Philippine Islands and Indonesia. She majored in biology and philosophy at the University of Rochester, and received a Ph.D. in theoretical ecology from Harvard University in 1971. She is Professor of Biological Sciences at Stanford University, and author of six books and over 140 papers in academic journals. She founded and directed the Earth Systems Program at Stanford, and was awarded for service to undergraduate education. She has also supervised over 30 doctoral and postdoctoral students. Joan lives in San Francisco, where she is active in community service.
Joan’s past research has focused on coevolutionary models that combine ecology with population genetics, on field studies of species interactions in the terrestrial fauna of Caribbean islands, and on the marine biology and oceanography of animals from the rocky intertidal zone of California. Her current research focuses on the mathematical theory of reproductive social behavior and is applying the cooperative game theory of bargaining and side payments to explain animal social dynamics, especially mating behavior. This current research is an outgrowth of her most recent book, Evolution’s Rainbow: Diversity, Gender and Sexuality in Nature and People, published in May 2004 by The University of California Press.
Darwin wrote that “males of almost all animals have stronger passions than females” and that “the female… with the rarest of exceptions is less eager than the male… she is coy.” Darwin imagined that male characteristics evolve because females select mates who are “more attractive… vigorous and well-armed,” just as “man can give beauty… to his male poultry” through selective breeding. This theory, called “sexual selection,” purports to explain the evolution of exceptional male ornaments like a peacock’s tail as the result of female choice, but now appears falsified and inadequate overall.
Ten findings across vertebrate species collectively refute sexual selection theory: many body types are not solely male or female; multiple forms of males and females occur within the same species; sex roles reverse; males forego opportunities to mate; female choice is not for attractive genes, but to manage male power; family size is negotiated between males and females; sexual mimicry has been claimed but never demonstrated; same-sex sexuality is common; mating promotes relationships independent of sperm transfer; and secondary sexual characters are often medals valued in same-sex social dynamics, not ornaments attractive in heterosexual mate choice.
A theory of social selection to replace sexual selection should include two new principles: transactions of reproductive opportunity, and social-inclusionary traits.
Dr. Lee M. Silver is a Professor at Princeton University in the Department of Molecular Biology and the Woodrow Wilson School of Public and International Affairs. He is the author of “Remaking Eden: How Genetic Engineering and Cloning Will Transform the American Family,” published in 15 languages. He has also authored an undergraduate textbook in genetics, and a textbook for professionals on mouse genetics. His current book, to be published by Ecco Press, is titled “Challenging Mother Nature: Biotechnology in a Spiritual World.” In 1993, Professor Silver was elected a Fellow of the American Association for the Advancement of Science (AAAS). In 1995, he received an unsolicited 10 year National Institutes of Health MERIT award. He has published over 180 scientific articles in the fields of genetics, evolution, reproduction, embryology, computer modeling, and behavioral science, and other scholarly papers on topics at the interface between biotechnology, law, ethics, and religion. He has been elected to the governing boards of the Genetics Society of America and the International Mammalian Genome Society. He was a member of the New Jersey Bioethics Commission Task Force formed to recommend reproductive policy for the New Jersey State Legislature, and has testified on reproductive and genetic technologies before U.S. Congressional and New York State Senate committees. He has appeared on numerous television and radio programs including NBC Nightly News with Tom Brokaw, the Jim Lehrer PBS News Hour, Nova, ABC Nightline, The ABC World Report with Peter Jennings, the Charlie Rose Show, 20/20, 60 Minutes, and many others in the U.S. and other countries.
Attempts to control the sex of a new-born child date back to the dawn of human civilization. But until recently, all putative methods were examples of impotent folklore or fraud (with a money-back guarantee). Today, however, the odds of having a girl or boy baby can be pushed far beyond the traditional one-to-one ratio. The least invasive approach involves a patented method for separating X and Y sperm from the ejaculate, followed by selective artificial insemination and conception in a woman’s uterus. When used alone, current X-sperm sorting technology increases the chances of a girl to 91%. A more accurate method of pre-pregnancy sex selection — approaching 100% for boys or girls — involves genetic analysis of individual embryos formed by in vitro fertilization. The “Promethean power” to pre-determine a child’s biological sex has alarmed both left-wing naturalists and religious fundamentalists.
Randolph Trumbach , Ph.D. City University of New York
Heterosexuality and Homosexuality:
Social Roles in Modern Western Societies
Randolph Trumbach is Professor of History at Baruch College and the Graduate Center of the City University of New York. He studies the origins of modernity in the eighteenth century, concentrating on the histories of the family, sexuality and religion. The patterns that emerge in the early eighteenth century have endured making the last three hundred years a single cultural unit.
His first book, The Rise of the Egalitarian Family (1978) examined aristocratic kinship and domestic relations. A double system of kindred and patrilineage (brought into focus by comparisons with Japan and Ethiopia) of long standing produced a structural egalitarianism in which land was controlled patrilineally but other relations were arranged through the looser bonds of friendship. In the middle of the century a new system of romantic marriage and affectionate child rearing (and here attachment theory helped the conceptualization) brought into existence a more self-conscious egalitarianism which modified traditional patriarchy and identified women primarily with their maternal roles. For the last twenty-five years Trumbach has studied sexual behavior, producing a series of articles on the origins of modern homosexuality and the first volume of a two-part study of the heterosexual/homosexual system, Sex and the Gender Revolution (1998). A comparative dimension has been crucial to arguing that before 1700 western societies were bisexual in behavior with sex between males organized by differences in age rather than through a passive transvestite population of males, and that after 1700 an exclusive homosexual male minority appeared and reorganized the behavior of the majority into an exclusive heterosexuality.
Michael Rocke’s study of Renaissance Florence has established statistically that c. 1450 at least one western society was universally bisexual with sex between males organized by differences in age. The sex surveys of the 1990s in England, France and the United States establish the coexistence of homosexual minority under five percent and an overwhelming heterosexual majority. The transformation from one system to another began in northwestern Europe in the generation after 1700. It subsequently spread to central, eastern and southern Europe, reached Japan in the early twentieth century, and seems to be about to become worldwide. In Europe, the transformation first began among men and seems to have become central to women’s identities only in the twentieth century, especially after 1960.
Sexual interaction between homosexual men and the heterosexual majority has occurred throughout the last three centuries but sex with male adolescents became increasingly controversial in the twentieth century and sex with adult male heterosexuals probably declined markedly after 1960 due to the reorganization in women’s behavior. This has been accompanied by a marked decline in the age of puberty in the twentieth century. But there does not seem to be any easily identifiable biological reason for the transformation from a bisexual to a heterosexual/homosexual system, which began after 1700.
Eric Vilain, M.D., Ph.D. was born in Paris, France and is currently an Associate Professor in the Departments of Human Genetics, Pediatrics and Urology at UCLA. Dr. Vilain received his B.S. in Biochemistry at the Universite Pierre et Marie Curie in 1987 and then his Ph.D. in 1994 at the Pasteur Institute. In 1995, Dr. Vilain received his M.D. at the Faculte de Medecine Necker Enfants Malades. Dr. Vilain assumes the positions of Chief of the Division of Medical Genetics at UCLA, Director of Female Sexual Medicine in the Department of Urology and Graduate Advisor in the Department of Human Genetics. He serves on several national committees on intersexuality. He has received numerous awards, notably from the NIH and the March of Dimes. Dr. Vilain is an expert in the field of the genetics of sexual development. He has deciphered a large number of molecular mechanisms responsible for intersexuality in humans, such as mutations in the sex-determining genes SRY and SOX9. His laboratory is working on the mechanisms of early gonadal development and brain sexual differentiation.
What is the definition of sex? Common sense dictates that males and females should be classified by the appearance of their genitals. The biological reality is more complex, in terms of both variability and mechanisms.
If the aspect of external genitalia is the litmus test for defining males and females, the spectrum of genital appearances becomes an immediate issue. Clitoris and penis, of common embryologic origin, have no clear definition for their respective size, and all intermediate forms exist in nature. Labia and scrotum (the male and female counterparts of the developing genital folds) also exist in a wide variety of intermediates.
Parameters of biological sex, in addition to the external genitalia, include chromosomal sex (XX or XY), genetic sex (presence or absence of the SRY gene or of other genes of the sex determining pathway), gonadal sex (testicular or ovarian tissue), hormonal sex (testosterone or estradiol), internal reproductive structures (uterus or epididymis) or brain sexual dimorphisms. Intersexuality, defined broadly as any discrepancy between the various aspects of biological sex, is an invaluable model to understand the mechanisms of sexual development, and a striking example of the difficulty to easily categorize individuals in a sexual binary system. The law often establishes rules of social conduct between men and women (for instance to delineate marriage) without referring to the underlying biological complexities of defining males and females.
On the Flexibility of Human Mating Preferences: A Social Role Analysis
Sex Chromosomes and the Future of Men
Evolutionary Aspects of Gender and Sexuality
Sex, God and Unethical Behavior
Heterosexuality and Homosexuality: Social Roles in Modern Western Societies
Between a Man and a Woman
Thode, Elizabeth. “UCLA holds third-annual conference on genetics, gender.” UCLA Daily Bruin 2005 January 28; 3. SITE