OFFSPRING
HUMAN FERTILITY BEHAVIOR IN BIODEMOGRAPHIC PERSPECTIVE
Kenneth W. Wachter and Rodolfo A. Bulatao, Editors
THE NATIONAL ACADEMIES PRESS
Washington, D.C.
www.nap.edu
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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This study was supported by Award No. NO1-OD-4-2139, TO #71 to the National Academies from the National Institute for Child Health and Human Development. Additional funding was provided by the Andrew W. Mellon Foundation. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
Library of Congress Cataloging-in-Publication Data
Workshop on the Biodemography of Fertility and Family Behavior.
Offspring : human fertility behavior in biodemographic perspective : proceedings of a workshop / Kenneth W. Wachter, Rodolfo A. Bulatao, editors.
p. cm.
“Panel for the Workshop on the Biodemography of Fertility and Family Behavior.”
Includes bibliographical references and index.
ISBN 0-309-08718-X
1. Fertility, Human—Congresses. 2. Demography—Congresses. I. Title: Human fertility behavior in biodemographic perspective. II. Wachter, Kenneth W. III. Bulatao, Rodolfo A., 1944- IV. Title.
QP251.W665 2003
304.6’32—dc21
2003000077
Additional copies of this report are available from the
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Suggested citation: National Research Council. (2003). Offspring: Human Fertility Behavior in Biodemographic Perspective. Panel for the Workshop on the Biodemography of Fertility and Family Behavior. Kenneth W. Wachter and Rodolfo A. Bulatao, eds. Committeee on Population, Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press.
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PANEL FOR THE WORKSHOP ON THE BIODEMOGRAPHY OF FERTILITY AND FAMILY BEHAVIOR
KENNETH W. WACHTER (Chair),
Department of Demography, University of California, Berkeley
JOHN N. HOBCRAFT,
Population Investigation Committee, London School of Economics
JEROME KAGAN,
Department of Psychology, Harvard University
HILLARD S. KAPLAN,
Department of Anthropology, University of New Mexico
HANS-PETER KOHLER,
Research Group on Social Dynamics and Fertility, Max Planck Institute for Demographic Research, Rostock, Germany
DAVID LAM,
Population Studies Center, University of Michigan, Ann Arbor
JANE MENKEN,
Institute of Behavioral Sciences, University of Colorado, Boulder
GERALD P. SCHATTEN,
Department of Obstetrics, Gynecology and Reproductive Sciences and Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine
RODOLFO A. BULATAO, Study Director
ANA-MARIA IGNAT, Senior Project Assistant
COMMITTEE ON POPULATION
(June 2000)
JANE MENKEN (Chair),
Institute of Behavioral Sciences, University of Colorado, Boulder
ELLEN BRENNAN-GALVIN,
Woodrow Wilson Center for International Scholars, Washington, DC
JANET CURRIE,
Department of Economics, University of California, Los Angeles
JOHN N. HOBCRAFT,
Population Investigation Committee, London School of Economics
CHARLES B. KEELY,
Institute for the Study of International Migration, Georgetown University
DAVID I. KERTZER,
Department of Anthropology, Brown University
DAVID LAM,
Population Studies Center, University of Michigan, Ann Arbor
CYNTHIA B. LLOYD,
Population Council, New York
W. HENRY MOSLEY,
Department of Population and Family Health Sciences, Johns Hopkins University
ALBERTO PALLONI,
Center for Demography and Ecology, University of Wisconsin, Madison
JAMES W. VAUPEL,
Max Planck Institute for Demographic Research, Rostock, Germany
KENNETH W. WACHTER,
Department of Demography, University of California, Berkeley
LINDA J. WAITE,
Population Research Center, University of Chicago
BARNEY COHEN, Director
Preface
Having children is a biological imperative for the survival of a group, and a wanted child can be a biological coup for a couple, a supreme biological moment—of possible peril and triumph—for a woman. Yet demographic interest in fertility has, for decades, been driven less by such concerns than by the threat of rapid population growth and the issue, for couples and women, of unplanned fertility. This volume seeks to encourage more balance and depth in the treatment of fertility in population studies. It suggests that many fertility behaviors that concern demographers may follow biodemographic templates, are influenced by genetic endowment, are triggered through hormonal pathways, and have been shaped in specific directions in the course of human evolution.
Since the middle of the 20th century, the contrast between small families in developed countries and large families and burgeoning populations in developing countries has fueled concern about deepening poverty, global inequality, and escalating environmental burdens. These concerns have not disappeared, as global population continues to expand. Yet much of the expansion is now effectively a hangover from the high-fertility decades, and many countries, both developed and developing, have entered an era of subreplacement fertility.
The confluence of the largely successful (though still incomplete) worldwide effort to tame high fertility and the emergence of genetic approaches to understanding human behavior provide a stimulus to review the focus of demographic work on fertility, to enlarge its concerns with biological and evolutionary questions. The Committee on Population took on this task with the understanding that researchers in the area were pursuing a variety
of independent approaches that required a common, unifying focus. Some work in the area, such as studies of twins and adoptees, has also generated controversy, despite being pursued aggressively. With advice from the Committee on Population, the Board on Life Sciences, and the Institute of Medicine’s Board on Neuroscience and Behavioral Health, the National Research Council (NRC) appointed a panel to organize a workshop on the topic. This volume is the result.
The papers contained in this volume were presented at the Workshop on the Biodemography of Fertility and Family Behavior, held at the National Academies in Washington, D.C., in June 2002, building on a preliminary meeting in February 2002 at the Beckman Center in Irvine, California. The workshop in a sense complemented an earlier workshop in April 1996 on biodemographic aspects of longevity (published as Between Zeus and the Salmon: The Biodemography of Longevity). Both workshops brought together demographers, evolutionary theorists, geneticists, and biologists to consider questions at the interface between the social sciences and the life sciences.
The papers were subsequently reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the NRC’s Report Review Committee. The purpose of this independent review was to provide candid and critical comments to assist the institution in making the published volume as sound as possible and to ensure that the volume meets institutional standards for objectivity, evidence, and responsiveness to the study charge.
We thank the following individuals for contributing to the review: Nicholas G. Blurton Jones (University of California at Los Angeles), Sue Carter (University of Illinois at Chicago), Peter T. Ellison (Harvard University), John Haaga (Population Reference Bureau), Jennifer Harris (National Institute on Aging), Kristin Hawkes (University of Utah), Jerome Kagan (Harvard University), John J. Lepri (University of North Carolina at Greensboro), Kimber McKay (University of Montana), Monique Borgerhoff Mulder (University of California, Davis), Gerald P. Schatten (University of Pittsburgh School of Medicine), Barbara Smuts (University of Michigan, Ann Arbor), Kim Wallen (Emory University), and Maxine Weinstein (Georgetown University). The review of the entire volume was overseen by Michael Murphy of the London School of Economics. Although these individuals provided constructive comments and suggestions, responsibility for the content of this volume rests entirely with the authors and the institution.
Work on this project was stimulated and encouraged by Christine Bachrach of the National Institute for Child Health and Human Development and was supported under a contract with the institute. We are grateful for her continued attention to the core issues that the volume addresses and
to raising many questions that helped shape and enrich the volume. Additional funding was provided by the Andrew W. Mellon Foundation.
We are especially grateful to Kenneth Wachter, who chaired the panel that organized the workshop, providing the spark and vital judgments about appropriate participants. The other members of the panel that organized the workshop each made important contributions in helping delineate relevant topics, identify participants, and critique their contributions, and in some cases writing papers themselves. We also wish to thank Randy Bulatao who, as study director, enriched the workshop with broad perspectives and guided the endeavor through many challenges. Ana-Maria Ignat provided active staff support. Barbara Bodling O’Hare skillfully edited the report and Yvonne Wise guided the manuscript through the publication process.
Jane Menken, Chair
Committee on Population
Contents
Biodemography of Fertility and Family Formation |
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Genetic Influences on Fertility: Strengths and Limitations of Quantitative Inferences |
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Education, Fertility, and Heritability: Explaining a Paradox |
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The Neural Basis of Pair Bonding in a Monogamous Species: A Model for Understanding the Biological Basis of Human Behavior |
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Hormonal Mediation of Physiological and Behavioral Processes That Influence Fertility |
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Intraspecific Variability in Fertility and Offspring Survival in a Nonhuman Primate: Behavioral Control of Ecological and Social Sources |
Tables and Figures
TABLES
3-1 |
Number of Twins by Birth Cohort, |
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3-2 |
Completed Education for Females and Males by Birth Cohort, |
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3-3 |
Years of Primary and Secondary Schooling, |
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3-4 |
Number of Children Born Until End of 1998, |
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3-5 |
Females—Bivariate Ordered Probit Estimation for Number of Children, |
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3-6 |
Males—Bivariate Ordered Probit Estimation for Number of Children, |
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6-1 |
Per Annum Vital Rates for Wild-Foraging Amboseli Baboon Females (1971-1999) by One-Year Age Classes for Analysis in Projection Matrix Models, |
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6-2 |
Per Annum Vital Rates for Wild-Foraging Amboseli Baboon Males (1971-1999) by One-Year Age Classes for Analysis in Projection Matrix Models, |
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6-3 |
Impact of Foraging Environment on Various Life History Components, |
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6-4 |
Impact of Ecological and Social Factors on Various Life History Components, |
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7-1 |
Regressions for Percent of Families That Are Polygynous Among Foragers, |
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7-2 |
The Wives of Despots, |
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10-1 |
Humans’ Expectable Environments of Rearing, |
FIGURES
3-1 |
Bivariate behavioral genetics model for education and fertility, females, |
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3-2 |
Bivariate behavioral genetics model for education and fertility, males, |
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3-3 |
Cohort and education effects on within-MZ correlation, |
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5-1 |
Schematic diagram of the hypothalamic-pituitary-gonadal axis, |
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5-2 |
Diagrammatic representation of changes in plasma levels of estradiol, progesterone, LH, FSH, and portal levels of GnRH over the human menstrual cycle, |
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5-3 |
Examples of the pulsatile pattern of LH secretion in a woman during the late follicular phase (A) and midluteal phase (B) of the menstrual cycle, |
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5-4 |
Schematic diagram of factors that mediate the effects of psychological stress on the activity of the hypothalamic-pituitary-gonadal axis, |
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6-1 |
Duration of several life history stages as a function of body size in anthropoid primates, |
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6-2 |
Proportion of elasticity in the matrix model attributable to immature survival, fertility, and adult survival, |
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6-3 |
Projected population growth (or relative fitness) for different levels of first-year survivorship holding all other survival and fertility values to those in Table 6-1, |
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6-4 |
Amboseli study groups that contributed data to the present analyses, |
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6-5 |
High density results in lower reproductive rate (longer interbirth intervals following a surviving offspring), |
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6-6 |
Age of reproductive maturity and reproductive rate (measured as in Figure 6-5) are functions of social status, |
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6-7 |
Daughters’ social status as predicted by that of their mothers, |
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6-8 |
Overview of behaviors affecting fertility and offspring survival by fully wild-foraging baboons in Amboseli over three decades, |
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7-1 |
Production as a function of the capital stock, |
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7-2 |
Offspring viability isoclines (indifference curves) as a function of male and female inputs, |
7-3 |
Net food production and survival: Human foragers and chimpanzees, |
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7-4 |
Frequency distribution of percentage of marriages that are polygynous among foragers, |
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7-5 |
Father’s probability of ceasing to live with his child before the age of 6, |
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7-6 |
Living arrangements of I.D. Mkize High School students in Guguletu, South Africa, |
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9-1 |
Temporal relationship of adrenarche and puberty in human males, |
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9-2 |
Causal relationship of adrenarche and pubertal maturation, |
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9-3 |
Schematic representation of the impact of gonadal and adrenal hormones on reproductive strategies, |
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9-4 |
Conceptual model of biological dimension of adolescent sexual behavior, |
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10-1 |
Scheduling in timing of reproductive events in diverse human populations, |
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10-2 |
Secular trend in timing of puberty in terms of life history, |
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10-3 |
Representative endocrine axes, pathways, and interrelations, with particular regard to resource partitioning, |
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11-1 |
Number of live births by years of schooling for married women, ages 45 to 54, in Brazil 1984, and for black South Africans, 1995-1998, |
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11-2 |
Employment rates by years of schooling for married women, ages 35 to 44, in Brazil, 1984, and for black South Africans, 1995-1998, |
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11-3 |
Natural logarithm of monthly wages by years of schooling (relative to women with zero schooling) for married women, ages 35 to 44, with positive wages, in Brazil, 1984, and for black South Africans, 1995-1998, |
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11-4 |
Mean years of schooling of 15-year-olds by mother’s education, in Brazil, 1984, and for black South Africans, 1995-1998, |