The supply of, and demand for, child brides in India

One of the targets embedded within Sustainable Development Goal #5 is to eliminate child marriage. However, the practice of child marriage remains surprisingly high in some countries. UNICEF noted in 2018 that:

...approximately 650 million girls and women alive today were married before their 18th birthday. While the global reduction in child marriage is to be celebrated, no region is on track to meet the Sustainable Development Goal target of eliminating this harmful practice by 2030.

So, what explains the practice of child marriage? This 2017 article by Peter Leeson (George Mason University) and Pablo Suarez (New York University), published in the Journal of Economic Behavior & Organization (ungated version here), looks at child brides in India. Leeson and Suarez adopt a framework grounded in supply and demand. Specifically:

Our theory is grounded in son preference: parental taste for sons over daughters, common in developing countries. In trying to produce sons, son-preferring couples sometimes produce daughters. To afford the sons they want, some of these couples must dispose of their unwanted daughters, one way of which is to marry them off prematurely, creating a supply of prepubescent brides.

Son-preferring couples invest fewer resources in the care of their young daughters than their young sons, so more males survive to traditional marriage age than females. To find brides in the face of this sex ratio imbalance, some traditional marriage-aged men must reach into younger female cohorts, requiring them where that imbalance is severe to reach into prepubescent cohorts, creating a demand for prepubescent brides.

So, a preference for sons rather than daughters leads to both a supply of child brides as well as a demand for child brides. Leeson and Suarez use data from India to test their theory. India is a useful case study because India is "one of the most son-preferring and child-bride populous nations in the world". There is also substantial variation in son preference and child brides across states in India:

Prepubescent brides are most common in the northern and central regions of the country and less common in the south and northeast. In the northern state of Rajasthan, for example, in 1993, more than 17% of women who had ever married did so before puberty; in the southern state of Tamil Nadu, less than 0.5% did so...

Also like child brides, son preference in India is most pronounced in the north and least pronounced in the south. In the northern state of Rajasthan, for example, in 1993, the average ever-married woman’s ideal son/daughter ratio was nearly 1.7; in the southern state of Tamil Nadu, it was just 1.15. 

The key facts in the quote above already point to a correlation between son preference and the incidence of child brides, since both are higher in northern states, and lower in southern states. However, Leeson and Suarez put the theory to the test more rigorously, using data from the 1992-1993 National Family Health Survey (NFHS). While the NFHS data are cross-sectional, they construct a pseudo-panel dataset made up of different five-year age cohorts of women. That allows Leeson and Suarez to control for:

...unobserved cultural differences relating to son preference or marriage practices between people in different states and between older people and younger ones.

Controlling for underlying time-invariant differences between states, and common time trends across states, is important. Based on this setup, Leeson and Suarez find that:

...stronger son preference is associated with the birth of more unwanted daughters, younger postpubescent-female age at marriage, and a higher incidence of prepubescent brides. Moreover, son preference has a stronger positive association with prepubescent brides where poverty is more extreme...

This supports their theory that son preference drives an increase in supply of, and demand for, child brides. That highlights the challenge of achieving the target in SDG #5. Son preference is a cultural characteristic that may take years, if not generations, to alter. And India has one of the world's most imbalanced sex ratios, which will be a further contributing factor. Unfortunately, the Leeson and Suarez paper is silent on how countries might address the problem of child marriage. Prohibition isn't working, and I'd hate to think that we simply need to wait for generational change. Perhaps achieving some of the other targets in SDG #5, which focuses on the empowerment of women and girls, will lead to spillover reductions in child marriage? We can only hope.