Biased Childhood Sex Ratios and the Economic Status of the Family in Rural China

Demographers have consistently found that in human populations male births are slightly more frequent than female births. Data from several European countries over different periods of time show that, on average, about 105 to 106 boys are born for every 100 girls (Coale, 1991; Johansson and Nygren, 1991). While a sex ratio at birth falling in this range (105 to 106) has often been considered "normal," in recent years demographic surveys have shown that in several Asian countries sex ratios at birth appear to be significantly higher than 105, indicating an unusually high number of male births relative to female births. China, Taiwan, Hong Kong, South Korea, India, and Bangladesh are some of the countries where abnormally high sex ratios at birth have been recorded (Zeng et al, 1993; Park and Cho, 1995; Kumar, 1989; United Nations, 1995). These findings have fueled a debate on whether the bias in sex ratios may be the result of preference for sons and parental behavior aimed at producing more male children than biologically normal. Such behavior may include abortion of female fetuses (made possible by the spread of techniques to determine the gender of fetuses) as well as female infanticide. The debate has been especially heated in China, where the institution of a one-child policy at the end of the 1970s is believed by many to have caused a sharp increase in female infanticide and in selective abortion aimed at assuring that the one child is a boy. Data from China's 1988 two-per-thousand fertility survey show that the sex ratio at birth was above 106 in each year between 1980 and 1984, and above 110 in 1985, 1986, and 1987 (Johansson and Nygren, 1991). The idea that sex ratios are being affected by parental behavior seems to be supported by the observation that Chinese sex ratios increase with birth order, hi 1987, for example, sex ratios were close to normal for first-order births (106.7), but much higher for higher-parity ones (112.6 for second births, 118.9 for third, 118.1 for fourth, and 125.6 for fifth and higher) (Johansson and Nygren, 1991). The common interpretation is that parents whose first child is a girl may be willing to resort to anything (including abortion and infanticide) to make sure that their next child is a boy.1 In this paper, I look at childhood sex ratios in rural China and examine the factors that may affect the probability of a surviving child to be male or female. In particular, I study the effect of the economic status of the parents on a surviving child's gender. EXPLAINING BIASED SEX RATIOS Why do we observe a bias in the sex ratios of Chinese children? Demographers point out that there are several possible sources of such a bias (see, e.g., Hammel et al., 1983): * A bias in the primary sex ratio (sex ratio at conception); * A bias in the secondary sex ratio (sex ratio at birth); * Sex-differential underreporting of newborns; * Sex-differential post-natal mortality; * Sex-differential migration by gender. Biased sex ratios may result from the conception of an unusually high number of male fetuses. Research shows that there are circumstances under which this might happen (for example, conception early or late in a woman's fertile period tends to result in a higher number of male births) (Sieff, 1990). It seems very unlikely, however, that biases as large as the Chinese one could be observed because of these effects, nor is there any evidence that primary sex ratios in China are any different than in other countries. The fact that the bias in Chinese sex ratios is a relatively recent phenomenon also makes it unlikely that racial or ethnic factors could explain the current high ratios (Johansson and Nygren, 1991). Secondary sex ratios are more easily affected by parental behavior. The ability to identify the gender of the fetus (and to abort fetuses of the unwanted gender) gives parents the power to turn a normal sex ratio at conception into a biased sex ratio at birth. …