Social Identity

Ancestral ecological endowments and contemporary sex ratios

  • Blog Post Date 15 March, 2019
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Gautam Hazarika

University of Texas Rio Grande Valley

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Sudipta Sarangi

Virginia Polytechnic Institute and State University

About six million women are ‘missing’ each year from the world, of which 2 million are from India alone. This article finds that there are proportionately more missing women in regions with poorer ancestral ecological endowments, both across countries and in Indian districts. It suggests that there was greater gender inequality in terms of command of resources in prehistory in less endowed regions, and the underlying behaviours have been culturally transmitted to the present as norms.


The sex ratio in India continues to be highly skewed in favour of men – there are 1.08 males per female in the total population. This skewed ratio is recorded at birth itself and can be attributed to the son-preference phenomenon. For instance, conditional on the firstborn being a female, the adjusted sex ratio for the second birth in a sample of 133,738 births in 1997 was 1.32 boys per girl. Jha et al. 2006). And if both the first two children were females, the adjusted sex ratio was 1.39 boys per girl. The corresponding numbers were 1.10 and 1.18 respectively if the first two children were boys, indicating that the son preference is a major cause of abortion. Consequently, even by conservative estimates, half a million female births are ‘missing’ every year in India.

Figure 1. Sex ratio in India: 1901-2011

Source: Census of India, 2011. 

However, this is not just an at-birth phenomenon. Anderson and Ray (2012) find that there are missing women at every age. Figure 1 plots sex ratio, defined as the number of females per 1,000 males, in India since 1901. Ironically, there were more females per 1,000 males in 1901 (and until 1961) than today. Sex ratio in 2011 is roughly the same as 50 years ago in 1961. This is a worrying trend because Indians are, on average, both richer and more educated than they were 50 years ago. Shockingly, it has actually declined in many states despite improvements in literacy rates in those states over the same time period.1 An important question for policymakers then is: Can we identify the factors that determine the cultural norms underlying son preference, and gender inequality in general, that may be responsible for the missing women in India and elsewhere?

Agricultural practices and gender norms

A recent strand of literature studies the role of historical agricultural practices in shaping gender norms regarding the appropriate role of women in the society, which arguably exist even today because of cultural persistence. For instance, Alesina, Giuliano, and Nunn (2013) illustrate Boserup’s (1970) hypothesis that societies whose ancestors practiced plough agriculture have developed less gender equal norms simply because the use of plough led to specialization of labour whereby women made their contribution from home. Consistently, they find that female participation in the labour force, national parliaments, and entrepreneurial activities, are lower in societies whose ancestors practiced plough agriculture. Hansen, Jensen, and Skovsgaard (2015) follow Diamond (1987) in arguing that the move to agriculture itself promoted patriarchal values and beliefs. They argue that these notions have become stronger over time and are more persistent in countries that experienced the Neolithic revolution (agricultural revolution in the Neolithic period2 earlier. They present consistent evidence that gender roles are more unequal in countries with longer histories of agriculture. 

Ancestral ecological endowments and missing women

Our recent research (Hazarika, Jha, and Sarangi, forthcoming) furthers this line of inquiry by examining the link between ancestral ecological endowments and sex ratio, both across countries and across Indian districts. We find that there are proportionately more missing women, measured as female-male sex ratios in 2013, in countries whose ancestral ecological endowments were poorer. Note that these sex ratios have been adjusted to account for migrations across countries. We obtain similar results using 2001 Census data at the district-level from India. We argue that there was greater gender inequality in prehistory in regions less endowed with ecological resources. Consequently, the underlying behaviours relating to greater gender inequality over command of resources have been culturally transmitted to the present as norms. 

In our study, a country’s ancestral ecological endowment is taken to be the average annual caloric yield per hectare of the crops grown there. Note that we restrict our analysis to crops grown prior to 1500 A.D. or pre-Columbian crops3 since the agricultural landscape was greatly altered by the Columbian Exchange of crops between the New and Old Worlds. The computation of caloric yields is based on a method proposed by Galor and Ozak (2016) that takes into account agro-climatic conditions and population migration. In other words, to better extrapolate into the past when agricultural technology was primitive, our measure of ancestral ecological resources considers potential crop yields based only on rain-fed and low-input conditions. Following Jones and Mann (2004), we argue that this extrapolation of potential crop yield data to the past is possible since the world’s climate has been fairly stable for at least the past one to two millennia. 

The link between ancestral ecological resources and missing women is shown to hold even after taking into account a variety of confounding factors like the plough use and years since transition to agriculture. Additionally, our cross-country analysis also controls for current economic conditions, institutions, democracy, and national legal systems, among a host of other factors. Moreover, Carranza (2014) argues that girls have lower economic values in areas with a greater fraction of loamy relative to clayey soils since the former allows for deep tillage and thereby reduces the need for agricultural tasks traditionally undertaken by women. She finds that Indian districts that are endowed with a greater share of loamy soils have a smaller share of female agricultural labourers, and a greater number of missing female children. Our cross-district findings are shown to be robust to the inclusion of district’s endowments of loamy soils.

A potential mechanism

Our research differs from the studies mentioned above in a very important way: Our focus is on gender inequality in well-being, rather than on gender roles. In fact, we find that there is no significant relationship between ancestral ecological endowments and current female labour force participation indicating that the effect of ancestral ecological resource scarcity on missing women is independent of gender roles.4 Our motivation comes from studies that have presented evidence of a connection between resource scarcity and gender inequality in history and prehistory. For instance, there is evidence suggesting that prehistoric women became shorter relative to men during economic scarcity suggesting that scarcity has relatively greater adverse impact on women’s share of nutrition (Cohen and Bennett 1993). Resource environments have also been regarded as an important factor in determining the markedly different gender norms in two very similar species of apes – chimpanzees and bonobos (Wrangham 1986). Finally, anthropologists Hayden, Deal, Cannon, and Casey (1986) find that the lack of subsistence resources is liable to diminish women’s status in the domestic and political spheres. We therefore argue that pre-existing gender inequality in antiquity, gets exacerbated in countries with poor agro-ecological endowments and eventually becomes a cultural norm that persists even today. 

Our work suggests that women’s share in resources shrank during times of scarcity not because their bargaining power was adversely impacted, but possibly because theirbargaining power was already lower than men. Essentially, given the strenuous nature of agricultural work, food production was already concentrated in men’s hands (Hansen, Jensen, and Skovsgaard 2015). On top of that, persistent local geography meant that the scarcity born out of poor ecological endowments did not change over time. Consequently, the resulting gender inequality in the division of resources was also persistent and eventually became a cultural norm. 

Concluding remarks

According to a World Bank estimate, 6 million women are missing every year. These women come from every age-group: 23% are never born, 10% are missing in early childhood, 21% in the reproductive ages, and 38% in the age of 60 and above (World Bank, 2011). From the policy perspective, it is important to understand what factors are associated with an improvement in the sex ratio. Our study shows that soil endowments, by determining the yield of pre-Columbian crops, have an impact on missing women in India through the formation of cultural norms. This echoes the finding of Carranza (2014) who shows that presence of loamy or clayey (which require greater strength for tilling) soils can explain a part of the missing women in India. 

These findings have important policy implications as the Indian economy remains a significantly agrarian economy as far as employment is concerned.5 It seems that an attempt to increase the economic worth of women for instance, by creating more job opportunities for them may lead to an improvement in the sex ratio. While it takes a long time for the cultural norms to change, awareness programmes that promote the culture of gender equality and empowerment of women is a necessary step in the direction of reducing the number of missing women. 


  1. In Uttar Pradesh, for example, even though female literacy rate jumped by a staggering 17% during 2001-2011, the child sex ratio has declined. Sex ratio has worsened with rising literacy rates even in rich states like Maharashtra and Haryana. In fact, districts with low literacy rates have higher sex ratios in Haryana, the state with the worst sex ratio according to the Census 2011.
  2. Neolithic Revolution, also called the Agricultural Revolution, marked the transition in human history from small nomadic bands of hunter-gatherers to larger, agricultural settlements and early civilization around 10,000 B.C.
  3. The phrase ‘pre-Columbian’ refers to the period before the arrival of Christopher Columbus in America in 1492. Some examples of pre-Columbian crops grown in India include rice, sugarcane, millets, black pepper, wheat, coconuts, beans, cotton, plantain, tamarind, etc.
  4. This is further supported by the fact that the positive relationship between ancestral ecological endowments and missing women is robust to the inclusion of current female workforce participation rate.
  5. In 2012, 47% of the total employment in India was contributed by agriculture and allied activities while its value added to GDP (gross domestic product) was merely 18%. More importantly, 60% of total employed females were involved in agriculture and allied activities as opposed to 43% of total employed men. Notably, the share of agriculture and allied activities in GDP and employment for most of the developed economies is less than 5%.

Further Reading

  • Alesina, Alberto F, Paola Giuliano and Nathan Nunn (2013), “On the Origins of Gender Roles: Women and the Plough”, The Quarterly Journal of Economics, 128(2): 469-530.
  • Anderson, Siwan and Debraj Ray (2012), “The Age Distribution of Missing Women in India”, Economic and Political Weekly, 1 December, 87-95. Available here.
  • Boserup, E (1970), ‘Woman’s Role in Economic Development’, George Allen and Unwin Ltd., London.
  • Carranza, Eliana (2014), “Soil Endowments, Female Labor Force Participation, and the Demographic Deficit of Women in India”, American Economic Journal: Applied Economics, 6(4): 197-225.
  • Cohen, MN and S Bennett, (1993), ‘Skeletal Evidence for Sex Roles and Gender Hierarchies in Prehistory’, in BD Miller (ed.), Sex and Gender Hierarchies, Cambridge University Press, Cambridge.
  • Diamond, J (1987), The Worst Mistake in the History of the Human Race, Discover, Worthington.
  • Galor, Oded and Ömer Özak (2016), “The Agricultural Origins of Time Preference”, American Economic Review, 106(10): 3064-3103. Available here.
  • Hansen, Casper W, Peter S Jensen and Christian Skovsgaard (2015), “Modern Gender Roles and Agricultural History: The Neolithic Inheritance”, Journal of Economic Growth, 20(4): 365-404.
  • Hayden, Brian, M Deal, A Cannon and J Casey (1986), “Ecological Determinants of Women’s Status among Hunter/Gatherers”, Human Evolution, 1(5): 449-474.
  • Hazarika, Gautam, Chandan Kumar Jha and Sudipta Sarangi (2018), “Ancestral Ecological Endowments and Missing Women”, Journal of Population Economics, forthcoming. Available here.
  • Jha, Prabhat, Rajesh Kumar, Priya Vasa, Neeraj Dhingra, Deva Thiruchelvam and Rahim Moineddin (2006), “Low male-to-female sex ratio of children born in India: National survey of 1.1 million households”, The Lancet, 367(9506): 211-218.
  • Jones, PD and ME Mann (2004), “Climate over Past Millennia”, Review of Geophysics, 42(2): 1-42.
  • World Bank (2011), ‘World Development Report 2012: Gender Equality and Development’, World Bank, Washington, D.C.
  • Wrangham, RW (1986), ‘Ecology and Social Relationships in Two Species of Chimpanzee’, in DI Rubenstein, RW Wrangham (eds.), Ecological Aspects of Social Evolution in Birds and Mammals, Princeton University Press, Princeton.     
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