Abstract
In this chapter, we use evolutionary models of sex ratio variation to examine offspring sex ratios in Matlab, Bangladesh, from the 1960s to 2010, during which time sex ratios have shown a decreasing male bias. Evolutionary models lead us to examine particular aspects of family ecology, yielding predictions both unique from and similar to those proposed in the demographic literature. We examine three evolutionary models—the costs of reproduction model, the Trivers–Willard hypothesis, and the local resource competition and enhancement models. Our results support both the Trivers–Willard and local resource competition/enhancement model, but results for the costs of reproduction model are weak. In general, we find that variables associated with higher wealth, status, and engagement in agriculture are linked to more male-biased offspring sex ratios, while higher fertility, older age at marriage, and higher women’s education are associated with less male-biased sex ratios. We also examine how Bangladesh fits into the larger cultural area of South Asia known in the press and policy circles for its high sex ratios. We compare the correlates of sex ratio in Matlab to those in other parts of the region and discuss why sex ratios in Bangladesh are less male biased, despite shared cultural characteristics, such as son preference and dowry, which some argue “cause” high sex ratios in parts of India and Pakistan. We conclude with a discussion of the utility of evolutionary models and offer policy recommendations for the region.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Abeykoon, A. (1995). Sex preference in South Asia: Sri Lanka an outlier. Asia Pacific Population Journal, 10, 5–16.
Agnihotri, S. B. (1995). Missing females: A disaggregated analysis. Economic and Political Weekly, 30(33), 2074–2084.
Agnihotri, S. B. (2000). Sex ratio patterns in the Indian population: A fresh exploration. New Delhi: Sage.
Ahmed, S. S., & Bould, S. (2004). One able daughter is worth 10 illiterate sons: Reframing the patriarchal family. Journal of Marriage and Family, 66, 1332–1341.
Ambrus, A., Field, E., & Torero, M. (2010). Muslim family law, prenuptial agreements, and the emergence of dowry in Bangladesh. The Quarterly Journal of Economics, 125, 1349–1397.
Anderson, S., & Eswaran, M. (2009). What determines female autonomy? Evidence from Bangladesh. Journal of Development Economics, 90, 179–191.
Arnold, F., Choe, M. K., & Roy, T. K. (1996). Son preference, the family-building process and child mortality in India. Population Studies, 85, 1–34.
Arnold, F., Choe, M., & Roy, T. K. (1998). Son preference, the family-building process and child mortality in India. Population Studies 52, 301–315.
Arnold, F., Kishor, S., & Roy, T. K. (2002). Sex-selective abortion in India. Population and Development Review, 28, 759–785.
Asfar, R. (2009). Unraveling the vicious cycle of recruitment: Labor migration from Bangladesh to the Gulf States. Geneva: International Labor Organization.
Aziz, K. A. (1979). Kinship in Bangladesh. Dhaka: International Centre for Diarrhoeal Disease Research.
Barton, K. (2013). MuMIn: Multi-model inference. R package version 1.9.5. http://CRAN.R-project.org/package=MuMIn.
Bereczkei, T., & Dunbar, R. (2002). Helping-at-the-nest and sex-biased parental investment in a Hungarian Gypsy population. Current Anthropology, 43, 804–809.
Borgerhoff Mulder, M. (1998). Brothers and sisters: How sibling interactions affect optimal parental allocations. Human Nature, 9, 119–162.
Brooks, R. C. (2012). Asia’s missing women as a problem in applied evolutionary psychology? Evolutionary Psychology, 12, 910–925.
Brown, G. R. (2001). Sex-biased investment in nonhuman primates: Can Trivers & Willard’s theory be tested. Animal Behaviour, 61, 683–694.
Brown, G. R., & Silk, J. B. (2002). Reconsidering the null hypothesis: Is maternal rank associated with birth sex ratios in primate groups? Proceedings of the National Academy of Sciences, 99, 11252–11255.
Burnham, K. P., & Anderson, D. R. (2002). Model selection and multi-model inference: a practical information-theoretic approach. New York: Springer.
Caldwell, B. (2005). Factors affecting female age at marriage in South Asia. Asian Population Studies, 1, 283–301.
Cameron, E. Z. (2004). Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard Hypothesis. Proceedings of the Royal Society, B, Biological Sciences, 271, 1723–1728.
Catalano, R., Bruckner, T., Gould, J., Eskenazi, B., & Anderson, E. (2005). Sex ratios in California following the terrorist attacks of September 11, 2001. Human Reproduction, 20, 1221–1227.
Census of India. (2011). Provisional population totals. http://www.censusindia.gov.in/2011-provresults/data_files/india/Final_PPT_2011_chapter5.pdf. Accessed 12 March 2012.
Census of Japan. (2005). Ministry of internal affairs and communications. http://www.stat.go.jp/english/data/kokusei/. Accessed 06 May 2013
Chahnazarian, A. (1988). Determinants of the sex ratio at birth: Review of recent literature. Social Biology, 35, 214–235.
Chen, L. C. (1982). Where have the women gone? Insights from Bangladesh on low sex ratio of Indian population. Economic & Political Weekly, 17, 364–372.
CIA Factbook. (2012). The World Factbook, 2013. https://www.cia.gov/library/publications/the-world-factbook/fields/2018.html. Accessed 24 July 2006.
Clark, A. B. (1978). Sex ratio and local resource competition in a prosimian primate. Science, 201, 163–165.
Clark, S. (2000). Son preference and sex composition of children: Evidence from India. Demography, 37, 95–108.
Clarke, A.L., & Low, B.S. (2001). Testing evolutionary hypotheses with demographic data. Population and Development Review, 27, 633–660.
Coale, A. J. (1991). Excess female mortality and the balance of the sexes in the population: An estimate of the number of missing females. The Population and Development Review, 17(3), 517–523.
Coale, A. J., & Banister, J. (1994). Five decades of missing females in China. Demography, 31, 459–479.
Cockburn, A., Legge, S., & Double, M.C. (2002). Sex ratios in birds and mammals: can the hypotheses be disentangled? In I. Hardy (Ed.), Sex ratios: Concepts and research methods (pp. 266–286). Cambridge: Cambridge University Press.
Crawley, M. J. (2005). Statistics: An introduction to using R. West Sussex: Wiley.
Cronk, L. (2000). Female-biased parental investment and growth performance among the Mukogodo. In L. Cronk, N. A. Chagnon & W. Irons (Eds.), Adaptation and human behavior: An anthropological perspective. New York: Aldine de Gruyter.
Darwin, C. (1871). The descent of man. London: John Murray.
Das Gupta, M. (1987). Selective discrimination against female children in rural Punjab, India. Population and Development Review, 13, 77–100.
Das Gupta, M., & Bhat, P. N. M. (1997). Fertility decline and increased manifestation of sex bias in India. Population Studies, 51, 307–315.
Das Gupta, M., & Shuzhuo, L. (1999). Gender bias in China, South Korea, and India 1920-1990: Effects of war, famine, and fertility decline. Development and Change, 30, 619–652.
Das Gupta, M., Zhenghua, J., Bohua, L., Zhenming, X., Chung, W., & Hwa-Ok, B. (2003). Why is son preference so persistent in East and South Asia? A cross-country study of China, India, and the Republic of Korea. The Journal of Development Studies, 40, 153–187.
Dickemann, M. (1979). The ecology of mating systems in hypergynous dowry societies. Social Science Information, 18, 163–195.
D’Souza, S., & Chen, L. (1980). Sex differentials in mortality in rural Bangladesh. Population and Development Review, 6, 257–270.
Echavarri, R. A., & Ezcurra, R. (2010). Education and gender bias in the sex ratio at birth: Evidence from India. Demography, 47, 249–268.
Edlund, L. (1999). Son preference, sex ratios, and marriage patterns. Journal of Political Economy, 107, 1275–1304.
Emlen, S. T., Emlen, J. M., & Levin, S. A. (1986). Sex-ratio selection in species with helpers-at-the-nest. The American Naturalist, 127, 1–8.
Esteve-Volart, B. (2004). Dowry in rural Bangladesh: participation as insurance against divorce. London: London School of Economics.
Festa-Bianchet, M. (1996). Offspring sex ratio studies of mammals: Does publication depend upon the quality of the research or the direction of the results? Ecoscience, 3, 42–44.
Fisher, R. A. (1930). The genetical theory of natural selection. New York: Dover.
Flinn, M. (1988). Step and genetic parent/offspring relationships in a Caribbean village. Ethology and Sociobiology, 9, 335–369.
Fraser, R. S. (2011). Global labor markets and child gender preference in rural Bangladesh. Virginia: National Science Foundation.
Gibson, M., & Mace, R. (2003). Strong mothers bear more sons in rural Ethiopia. Proceedings of the Royal Society B, Biological Sciences, 271(Supp 1), S108–S109.
Gomendio, M., Clutton-Brock, T. H., Albon, S. D., Guinness, F. E., & Simpson, M. J. (1990). Mammalian sex ratios and variation in costs of rearing sons and daughters. Nature, 343, 261–263.
Guilmoto, C. (2009). The sex ratio transition in Asia. Population and Development Review, 35, 519–549.
Hardy, I. (Ed.). (2002). Sex ratios: Concepts and research methods. Cambridge: Cambridge University Press.
Helle, S., Lummaa, V., & Jokela, J. (2002). Sons reduced maternal longevity in preindustrial humans. Science, 296, 1085–1085.
Helle, S., & Lummaa, V. (2013). A trade-off between having many sons and shorter maternal post-reproductive survival in pre-industrial Finland. Biology Letters, 9. doi:10.1098/rsbl.2013.0034.
Hesketh, T., & Xing, Z. W. (2006). Abnormal sex ratios in human populations: Causes and consequences. Proceedings of the National Academy of Sciences, 103, 13271–13275.
Hill, K., & Kaplan, H. (1988). Tradeoffs in male and female reproductive strategies among the Ache. In L. Betzig, M. Borgerhoff Mulder, & P. Turke (Eds.), Human reproductive behaviour: A Darwinian perspective. Cambridge: Cambridge University Press.
Holman, D., & O’Connor, K. (2004). Bangladeshis. In M. Ember & C. Ember (Eds.), Encyclopedia of Medical Anthropology. New York: Kluwer Academic Press.
Hrdy, S. B. (2000). Mother nature: Maternal instincts and how they shape the human species. New York: Ballantine Books.
Hrdy, S. B., & Judge, D. (1993). Darwin and the puzzle of primogeniture: an essay on biases in parental investment after death. Human Nature, 4, 1–45.
Hudson, V. M. (2011). China’s census: The one-child policy’s gender-ratio failure. World Politics Review. http://www.worldpoliticsreview.com/articles/8731/chinas-census-the-one-child-policys-gender-ratio-failure. Accessed 12 June 2012
Hudson, V. M., & den Boer, A. M. (2004). Bare branches: The security implications of Asia’s surplus male population. Cambridge: Belfer Center for Science and International Affairs.
ICDDRB. (1981). Health and Demographic Surveillance System—Matlab. Demographic Studies in Rural Bangladesh: May 1969-April 1970. Dhaka: IDCCR, B.
ICDDRB. (2007). Health and Demographic Surveillance System—Matlab. 2005 Socio-economic Census (Vol. 38). Dhaka: ICDDRB.
ICDDRB. (2012a). Health and Demographic Surveillance System (Vol. 44). Registration of health and demographic events 2010, Scientific Report No. 117 (Vol. 44). Dhaka: ICDDRB.
ICDDRB. (2012b). Health and Demographic Surveillance System-Matlab, Registration of health and demographic events (1975 to 2010) workbook. Dhaka: ICDDRB.
James, W. H. (2009). The variations of human sex ratio at birth during and after wars, and their potential explanations. Journal of Theoretical Biology, 257, 116–123.
James, W. H. (2012). Hypotheses on the stability and variation of human sex ratios at birth. Journal of Theoretical Biology, 310, 183–186.
Johansson, S., & Nygren, O. (1991). The missing girls of China: A new demographic account. The Population and Development Review, 17(1), 35–51.
Johnson, C. N. (1988). Dispersal and the sex ratio at birth in primates. Nature, 332, 726–728.
Kabeer, N. (2001). Ideas, economics, and the ‘sociology of supply’: Explanations of fertility decline in Bangladesh. Journal of Development Studies, 38, 29–70.
Kaplan, H., & Lancaster, J. B. (2000). The evolutionary economics and psychology of the demographic transition to low fertility. In L. Cronk, N. Chagnon, & W. Irons (Eds.), Adaptation and human behavior: An anthropological perspective. New York: Aldine de Gruyter.
Keller, M., Nesse, R., & Hofferth, S. (2001). The Trivers-Willard hypothesis of parental investment: No effect in the contemporary United States. Evolution and Human Behavior, 22, 343–360.
Kokko, H., & Jennions, M. D. (2008). Parental investment, sexual selection and sex ratios. Journal of Evolutionary Biology, 21, 919–948.
Koziel, S., & Ulijaszek, S. J. (2001). Waiting for Trivers and Willard: Do the rich really favor sons? American Journal of Physical Anthropology, 115, 71–79.
Krackow, S., & Tkadlec, E. (2001). Analysis of brood sex ratios: Implications of offspring clustering. Behavioral Ecology and Sociobiology, 50, 293–301.
Nie, L. (2009). Essays on son preference in China during modernization. Dissertation Abstracts International, The Humanities and Social Sciences, 70, 1368.
Lazarus, J. (2002). Human sex ratios: adaptations and mechanisms, problems and prospects. In I. Hardy (Ed.), Sex ratios: concepts and research methods (pp. 287–311). Cambridge: Cambridge University Press.
Li, S. (2007). Imbalanced sex ratio at birth and comprehensive intervention in China. Paper presented at the 4th Asia Pacific Conference on Reproductive and Sexual Health and Rights, Hyderabad, India.
Mace, R. (1996). Biased parental investment and reproductive success in Gabbra pastoralists. Behavioral Ecology and Sociobiology, 38, 75–81.
Mace, R., & Sear, R. (1997). Birth interval and sex of children in a traditional African population: an evolutionary analysis. Journal of Biosocial Science, 29, 499–507.
McMillen, M. (1979). Differential mortality by sex in fetal and neonatal deaths. Science, 204, 89–91.
Miller, B. D. (1981). The endangered sex: Neglect of female children in rural north India. Ithaca: Cornell University Press.
Miller, B. D. (1989). Changing patterns of juvenile sex ratios in rural India, 1961 to 1971. Economic & Political Weekly, 24, 1229–1236.
Murthi, M., Guio, A. C., & Dreze, J. (1995). Mortality, fertility, and gender bias in India: A district-level analysis. Population and Development Review, 21, 745–782.
Mutharayappa, R. (1997). Son preference and its effect on fertility in India. National Family Health Survey Subject Reports (Vol. 3). Mumbai: International Institute for Population Sciences.
Myers, J. H. (1978). Sex ratio adjustment under food stress: Maximization of quality or numbers of offspring? The American Naturalist, 112, 381–388.
Navara, K. J. (2010). Programming of offspring sex ratios by maternal stress in humans: Assessment of physiological mechanisms using a comparative approach. Journal of Comparative Physiology B, 180, 785–796.
Nepali National Population Census. (2011). Government of Nepal central bureau of statistics. http://cbs.gov.np. Accessed 17 Feb 2013
Nowak, J. J. (1993). Bangladesh: Reflections on the water. Bloomington: Indiana University Press.
Pande, R. P., & Astone, N. M. (2007). Explaining son preference in rural India: The independent role of structural versus individual factors. Population Research and Policy Review, 26, 1–29.
Park, C. B., & Cho, N. H. (1995). Consequences of son preference in a low fertility society: Imbalance of the sex ratio at birth in Korea. Population and Development Review, 21, 59–84.
Psacharopoulos, G., & H. A. Patrinos. (2002). Returns to investment in education: A further update. The World Bank: Policy Research Working Paper 2881.
Quinlan, R. J., Quinlan, M. B., & Flinn, M. (2005). Local resource enhancement and sex-biased breastfeeding in a Caribbean community. Current Anthropology, 46, 471–480.
R Development Core Team (2012). R: A language and environment for statistical computing. Vienna: R Foundation for Statistical Computing.
Richards, S. (2008). Dealing with overdispersed count data in applied ecology. Journal of Applied Ecology, 45, 218–227.
Richards, S. A., Whittingham, M. J., & Stephens, P. (2011). A Model selection and model averaging in behavioural ecology: The utility of the IT-AIC framework. Behavioral Ecology and Sociobiology, 65, 77–89.
Rosenzweig, M. R., & Schultz, T. P. (1982). Market opportunities, genetic endowments, and intra-family resource distribution: Child survival in rural India. American Economic Review, 72, 803–815.
Sekher, T. V., & Hatti, N. (2010). Disappearing daughters and intensification of gender bias: Evidences from two village studies in South India. Sociological Bulletin, 59, 111–133.
Shenk, M. K. (2007). Dowry and public policy in contemporary India: The behavioral ecology of a social “evil”. Human Nature, 18, 242–263.
Shenk, M. K., Towner, M., Kress, H., & Alam, N. (2013). A model comparison approach shows stronger support for economic models of fertility decline. Proceedings of the National Academy of Sciences. doi:10.1073/pnas.1217029110.
Sieff, D. F. (1990). Explaining biased sex ratios in human populations: A critique of recent studies. Current Anthropology, 31, 25–48.
Silk, J. B., & Brown, G. R. (2008). Local resource competition and local resource enhancement shape primate birth sex ratios. Proceedings of the Royal Society of London, Series B, 275, 1761–1765.
Silk, J. B., Samuels, A., & Rodman, P. S. (1981). The influence of kinship and rank on affiliation and aggression between adult female and immature bonnet macaque. Behaviour, 78, 112–137.
Smith, E. A., & Smith, S. A. (1994). Inuit sex-ratio variation: Population control, ethnographic error, or parental manipulation. Current Anthropology, 35, 595–624.
Towner, M. C., & Luttbeg, B. (2007). Alternative statistical approaches to the use of data as evidence for hypotheses in human behavioral ecology. Evolutionary Anthropology: Issues, News, and Reviews, 16, 107–118.
Trivers, R. L., & Willard, D. E. (1973). Natural selection of parental ability to vary the sex ratio of offspring. Science, 179, 90–92.
Turke, P. (1988). Helpers at the next: Childcare networks on Ifaluk. In L. Betzig, M. Borgerhoff Mulder, & P. Turke (Eds.), Human reproductive behaviour: A Darwinian perspective. Cambridge: Cambridge University Press.
United Nations D. o. E. a. S. A. (2011). World Population Prospects, the 2010 Revision. http://esa.un.org/unpd/wpp/Excel-Data/fertility.htm. Accessed 12 June 2012.
van Schaik, C. P., Netto, W. J., van Amerongen, A. J. J., & Westland, H. (1989). Social rank and sex ratio of captive long-tailed macaque females. American Journal of Primatology, 19, 147–161.
van Willigen, J., & Channa, V. (1991). Law, custom, and crimes against women: The problem of dowry death in India. Human Organization, 50, 369–377.
Waldron, I. (1985). What do we know about causes of sex differences in mortality? A review of the literature. Population Bulletin of the United Nations, 18, 59–76.
Warton, D., Francis, K., & Hui, C. (2011). The arcsine is asinine: The analysis of proportions in ecology. Ecology, 92, 3–10.
Wells, J. (2000). Natural Selection and sex differences in morbidity and mortality in early life. Journal of Theoretical Biology, 202, 65–76.
Wilson, K., & Hardy, C. W. (2002). Statistical analysis of sex ratios: An introduction. In I. Hardy (Ed.), Sex ratios: Concepts and research methods (pp. 48–92). Cambridge: Cambridge University Press.
Zhou, R. (2007). Insight into human sex ratio imbalance: The more boys born, the more infertile men. Reproductive BioMedicine Online, 15, 487–494.
Acknowledgments
This research was funded by U.S. National Science Foundation Award No. BCS-0924630, and a Research Leave from the University of Missouri. We would like to thank the ICDDRB, our field assistants (Shifat Khan, Nargis Sultana, Latifun Nahar, Akterun Naher, Lutfa Begum, Mouloda Aziz, and Farhana Akand), and the people of Matlab for their help with this project. Finally, we would like to thank Michelle Fritts for her work on causes of child mortality.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2014 Springer Science+Business Media New York
About this chapter
Cite this chapter
Shenk, M., Towner, M., Starkweather, K., Atkisson, C., Alam, N. (2014). The Evolutionary Demography of Sex Ratios in Rural Bangladesh. In: Gibson, M., Lawson, D. (eds) Applied Evolutionary Anthropology. Advances in the Evolutionary Analysis of Human Behaviour, vol 1. Springer, New York, NY. https://doi.org/10.1007/978-1-4939-0280-4_7
Download citation
DOI: https://doi.org/10.1007/978-1-4939-0280-4_7
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4939-0279-8
Online ISBN: 978-1-4939-0280-4
eBook Packages: Humanities, Social Sciences and LawSocial Sciences (R0)