1. Sons Reduced Maternal Longevity in Preindustrial Humans
2. Supplemental information including data selection criteria and the description of different models and their estimated coefficients is available at www.demogr.mpg.de/publications/files/beisesupp.pdf
3. Voland E., Evol. Anthropol. 9, 134 (2000).
4. We thank Bertrand Desjardins of the Programme de Recherche en Démographie Historique of the University of Montréal for providing the data of the St. Lawrence valley. We also thank J. W. Vaupel for some crucial suggestions and the two anonymous reviewers for clarifying comments.
5. D. A. Roff The Evolution of Life Histories (Chapman & Hall NY 1992).