Women's and men's health differ in a variety of ways. Women have greater longevity than men, but during their lifespan women experience more morbidity. Scientists have investigated explanations for these differences, pursuing explorations of biological differences, such as those linked to the & cross; chromosome and those modulated by sex steroids (e.g., immune response). Other scholars have studied the differential socialization of girls and boys with respect to risk-taking behavior, sophistication about health and health-seeking behavior, and the social roles women and men play in their occupations and in their homes. Still others have examined sources of stress in women's and men's lives that might account for differences in health and disease patterns. The most likely explanations accounting for women's and men's different health experiences are complex and multivariate and may include differences in each gender's unique susceptibility to factors in their environments.

Recognizing the complexity of the topic, the Committee on Gender Differences in Susceptibility to Environmental Factors undertook the study within a framework that incorporated distinctions between sex and gender and defined environment in its broadest sense—inclusive of physical, biological, social, and cultural dimensions. As an initial step toward these fundamental understandings, our committee was assembled to review existing information, discuss issues with a larger group of interested individuals, and make recommendations for an initial set of priorities for work in this area.

Although the committee bears responsibility for the conclusions and recommended priorities in this report, I would be seriously remiss if I failed to acknowledge the contributions of many others to both the planning and conduct of the committee's activities. First, I owe thanks to the sponsors of this activity for posing the questions and initiating this study. Special thanks go to Dr. Vivian Pinn, director of the Office for Research on Women's Health (ORWH) at the

National Institutes of Health (NIH), for initiating this effort and to then deputy director, Dr. Anne Bavier, who served ably as the task leader in the initial stages of this project. I would also like to acknowledge the skillful work of Joyce Rudick, acting deputy director, ORWH, who graciously stepped into the role of task leader after Dr. Bavier's departure from ORWH.

One of the features of this small but important project was its multiagency sponsorship and interest. Joining ORWH in support of this project were Dr. Anne Sassaman, director, Division of Extramural Research and Training, and Dr. Gwen W. Collman, scientific programs administrator, both of the National Institute of Environmental Health Sciences, NIH, and Dr. Yvonne Maddox, deputy director, National Institute of Child Health and Human Development, NIH. The committee thanks Dr. Lynn Goldman, assistant administrator for prevention, pesticide, and toxic substances, and Dr. Margaret Chu, toxicologist from the Environmental Protection Agency. The committee also thanks Dr. Wanda Jones, associate director for women's health at the Centers for Disease Control and Prevention. Each of these agency representatives provided us with materials and helpful ideas during the course of this activity. In addition, the committee extends its appreciation and thanks to the many other federal agency representatives who were contacted for information throughout the activity and who attended the workshop.

The workshop speakers shared their extensive expertise and provided the committee with thoughtful insights and ideas during the discussion period. They also helped the committee shape its priority recommendations. Therefore, I thank our excellent speakers: Greg Cosma, assistant professor, Department of Environmental Health, Colorado State University; S. Katharine Hammond, associate professor of environmental health sciences, School of Public Health, University of California at Berkeley; Kenneth S. Korach, scientific program director, Environmental Diseases and Medicine Program, National Institute of Environmental Health Sciences, NIH; Shiriki Kumanyika, professor and chair in the Department of Human Nutrition and Dietetics, University of Illinois at Chicago; Bill Lasley, professor of reproductive medicine, Institute for Toxicology and Environmental Health, University of California at Davis; Peter N. Riskind, chief of neuroimmunology, Massachusetts General Hospital, Boston; and Jeanne Stellman, deputy chair, Department of Health Policy and Management, Columbia University School of Public Health, New York City.

Others who contributed to the work of the committee are Paul Phelps, consultant and writer who listened with us throughout the workshop and prepared a draft report of the workshop that captured the essence of the discussions. I also thank IOM senior project officer, Carolyn Fulco, for her critical and thoughtful review of earlier manuscripts; Claudia Carl, for her careful work in shepherding the report through review; Michael Edington, for his assistance in the publication of the document; and Ted Cron, our copy editor.

As the committee chair, I am acutely aware of the contributions that the committee staff has made to the success of the study. Special thanks go to Linda DePugh, administrative assistant, who made travel arrangements and meetings

as comfortable as possible and provided outstanding administrative support at the meetings and in the production of the report; to Jamaine Tinker, financial associate, for her masterful management of limited resources; to Elaine Lawson, research associate, who was instrumental in the early work of the committee in organizing materials, developing the initial analysis of the sponsoring agencies' research portfolio, and helping the committee identify speakers for the workshop; and to Valerie Setlow, division director, who provided her adept professional support to the committee throughout its tasks, report finalization, and review.

I would like to acknowledge the individual and collective efforts of the committee members. It seemed, a priori, that not all the questions, let alone all the answers, could emerge from such a small group. Yet, each member of the group assumed his or her tasks seriously and helped develop a very thoughtful agenda for agency action. It was a pleasure to have worked with this group of busy but unselfish professionals, who volunteered their time to share their knowledge and advice with the larger scientific community. In sum, their advice provides a good first step toward a fuller understanding of the unique and differential susceptibilities of women to environmental factors.

This report has been reviewed by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council's Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the authors and the Institute of Medicine in making the published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The content of the review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.

On behalf of the Institute of Medicine, I wish to thank the following individuals for their participation in the review of this report: Mary Ellen Avery, M.D., professor of pediatrics, Harvard Medical School; Brigid Hogan, Ph.D., investigator, Howard Hughes Medical Institute, Department of Cell Biology, Vanderbilt University School of Medicine; Maria New, professor and chair, Department of Pediatrics, and chief, Pediatric Endocrinology, New York Hospital, New York City; Michael Paolisso, Ph.D., systems professor of anthropology, Department of Anthropology, University of Maryland at College Park; Ellen K. Silbergeld, Ph.D., director, Program in Human Health and the Environment, University of Maryland at Baltimore; Helen Rodriguez-Trias, M.D., codirector, Pacific Institute for Women's Health, Western Consortium for Public Health, Los Angeles. While these individuals have provided many constructive comments and suggestions, responsibility for the final content of this report rests solely with the Committee on Gender Differences in Susceptibility to Environmental Factors and the Institute of Medicine.

A final comment: The principal focus of this report is on women. However, it lays the groundwork for the most logical next step: an evaluation of the analytical steps required to move to a gender-focus analysis, one that would involve

health outcomes for women and men. Work in the international field of women in development suggests that the most powerful analysis is to consider both women and men, and the relations and interactions between them in terms of particular outcomes, such as health. Women's health-seeking behavior and their ability to respond to environmental risk will in part be conditioned by their relationships with men, both from a cultural role perspective (i.e., what is appropriate for women and men to do) and what they actually do (behavior). Building a constituency of researchers and policymakers for gender differences in susceptibility to environmental factors will be fostered by a more inclusive and comparative focus.