Abstract How much of the increase in the sex ratio (males to females) at birth since the early 1980s in China is due to increased prenatal sex selection? I answer this question by exploiting the diﬀerential introduction of diagnostic ultrasound throughout China during the 1980s, which signiﬁcantly reduced the cost of prenatal sex selection. The improved local access to ultrasound technology is found to have resulted in a substantial increase in the sex ratio at birth. Furthermore, this eﬀect was driven solely by a rise in the sex ratio of higher order births, especially following births of daughters. I estimate that the local access to ultrasound increased the fraction of males by 1.3 percentage points for second births and by 2.4 percentage points for third and higher order births. Using the annual birth rate at the county level as a proxy for local enforcement of the One Child Policy, the eﬀects of ultrasound are found to be stronger for individuals under tighter fertility control. These ﬁndings suggest that the current trend in skewed sex ratios in China is signiﬁcantly inﬂuenced by prenatal sex selection. Several robustness checks indicate that these results are not driven by preexisting diﬀerential trends. JEL Classiﬁcation: I38, J13, J16, O33
I am particularly indebted to my dissertation advisor, Mark Duggan, and other committee members, John Ham, Melissa Kearney and Jeanne Lafortune for their comments and advice. I also wish to thank Avi Ebenstein, Lena Edlund, Raymond Guiteras, Soohyung Lee, Peter Murrell, Xiaobo Zhang and seminar participants at the University of Maryland, and the CES Nanning Conference for helpful comments. I am grateful to Hongbin Li and Yuyu Chen for generous assistance with data sources and useful discussions. All errors are my own. † Department of Economics, 3105 Tydings Hall, University of Maryland, College Park, MD 20742. Email: email@example.com
China has a signiﬁcant population sex imbalance in favor of males. It has been estimated that tens of millions of Chinese women are “missing” (Coale, 1991; Sen, 1990, 1992). Sen (1992) suggested that a substantial excess female mortality due to sex discrimination was responsible for the huge deﬁcit of females in China. Since then, the issue of “missing women” has received great attention from researchers and policy makers alike. The problem undoubtedly needs to be addressed because of its profound ethical implications for women’s welfare (Croll, 2000). In addition, concerns have also been raised about the adverse social consequences of the huge surplus of men (Ebenstein and Jennings, 2008; Edlund et al., 2007). The recent years have seen a worsening of the “missing women” problem in China as the ratio of male to female births continued to rise signiﬁcantly. As reported in the censuses, the sex ratio1 of the population age 0, which was 107.6 in 1982, has reached 117.8 in 2000. The rapid rise in the sex ratio at birth coincided with the introduction of the One Child Policy, and the increased access to fetal sex determination technologies, chieﬂy diagnostic ultrasound. Previous research suggests that the rising sex ratio at birth in China was mainly a result of the escalating incidence of sex-selective abortion (Banister, 2004; Chu, 2001; Miller, 2001).2 Existing empirical analysis based on large samples has generally attempted to infer indirect evidence of sex-selective abortion in China from sex ratio diﬀerentials by birth order, and by sex composition of older sibling(s). Speciﬁcally, the previous literature ﬁnds that the sex ratio at birth is close to the natural rate (roughly 106) for ﬁrst births, but increases steeply with parity following lower order female births (Zeng et al., 1993; Das Gupta, 2005; Ebenstein, forthcoming)....