the late 1990s and early 2000s (United Nations, 2017). The Republic of Korea, like some of its Asian counterparts, witnessed an excess of boys over girls for several years as well; however, since the mid-1990s, they have managed a turnaround on this front (Chung & DasGupta 2007; Guilmoto 2012a).

In the last four decades, the availability of prenatal sex diagnosis, coupled with access to abortion methods, has allowed couples with strong son preference to sex select before birth, and more effectively achieve their desired sex composition of children (Bongaarts & Guilmoto 2015; The World Bank 2012; Guilmoto 2012a). Between 1980 and 2015, the sex ratio at birth (SRB) – number of male births per female birth – in some countries increased from 1.07 to over 1.15 (United Nations 2017), representing a stark departure from the biological norm of 1.06 that would be seen without prenatal sex selection. Prenatal sex selection also accounted for an increasingly significant portion of the total missing girls during this period (Bongaarts & Guilmoto 2015).

Not surprisingly, bans on prenatal sex selection technology have been one of the most widely used measures by countries trying to curb the excess mortality of girls. Bans are a common legal tool used by governments to restrict socially “undesirable” behavior, and promote social equality (Sunstein 1994). Bans against child labor, discriminatory hiring, and underage drug-use are all examples of prohibitive legal measures that seek to protect vulnerable and/or discriminated groups, much like bans against the use of prenatal sex selection technology.

It is important to note, however, that prenatal sex selection is only one of the pernicious ways in which son preference manifests. Son preference can also trigger a range of postnatal sex discrimination strategies from infanticide, to abandonment, to differential care during infancy and early childhood. These strategies were the primary cause for the excess mortality of girls before the 1980s, and they continue to be used by parents who prefer sons, but do not have the financial means to access prenatal sex selection methods. Estimates by the United Nations (2011) suggest that in China and India in the 1990s and 2000s, infant mortality (probability of dying between birth and age 1 year) and child mortality (probability of dying between age 1 and age 5 years) was higher for girls than for boys, contrary to the biological norm.<sup>4</sup> From a policy perspective, sex selection – before or after birth – is cause for concern. While restrictions on prenatal sex selection particularly raise ethical concerns surrounding reproductive choice and abortion, what is strikingly clear is that prenatal (and postnatal) sex selection are stark indicators of the dismal status and systematic devaluation of girls and women today. In the longrun, as the excess of boys translates into the excess of men, these gender inequities are likely to be reproduced. Natural experimental evidence from Grosjean and Khattar (2015) suggests that today, in communities that were historically male-biased, people are less likely to favor women’s economic independence and empowerment. Marriage homogamy (on cultural grounds), and the

> 4 When boys and girls have similar access to resources and care, girls have a survival advantage over boys. As overall mortality declines during the epidemiological transition, this female survival advantage during childhood increases. In the case of India and China, however, the male to female ratio of child mortality (probability of dying between ages 1-4) is less than 100, indicating excess female child mortality. In countries without documented son preference, the sex ratio of child mortality is more than 100 (see United Nations 2011).

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