⎯ adherence to Confucian family traditions and Korean folk religions<sup>26</sup> as compared with Christians, whose religion has some strong roots outside of Korean traditions.

# **_Methods_**

Our analysis has four steps. First, we examined the relationship between women’s characteristics and their reported son preference in 1991 and 2003, using frequencies and chi-square tests (results not shown). Second, we used multivariate logistic regression analyses to estimate the odds ratio for the association between a respondent’s characteristics and having strong son preference, while adjusting for all the other characteristics in the model. This was done separately for 1991 and 2003 using the same variables for easy comparison, and a third regression was run including the variables available only for 1991, as well as a fourth regression used the pooled data from both the 1991 and 2003 surveys (Table 4). Third, we examined changes between the two survey years in the probability of reporting intense son preference, within a given subgroup of women. This was done by merging the 1991 and 2003 datasets, and conducting univariate logistic regression analyses for each selected characteristic of women (Table 5).

Fourth, we decomposed the contribution of two factors to the decline in the intensity of son preference between 1991 and 2003: changes in population composition and changes in social norms (Table 6). The first is the contribution attributable to increases in education and urbanization (“population composition”). This we estimate by holding the levels of son preference constant at those reported by specific education and urbanization categories of women in 1991, and increasing the proportions educated and living in urban areas from their 1991 levels to their 2003 levels. The second is the contribution of changes in social norms. This we estimate by holding the population composition constant at their 2003 levels, and changing the level of son preference of each socio-economic category of women from their 1991 levels to their 2003 levels. We also estimated the independent contribution of each of the variables in the model. The decomposition methodology used is described in the Appendix.

To assess the robustness of our estimates of the contribution of each independent covariate, we also did the decomposition without the constant term (results not shown).<sup>27</sup> A rationale for this is to make the estimates for the independent contribution of each of the variables in the model more directly comparable, since the constant term refers to an underlying shift and is therefore applicable only to the part associated with changes in ideas of son preference.

# **4.   Trends in son preference**

# **_Trends in the manifestation of son preference:_**

Figure 2 shows the trends in the sex ratio at birth, and the trend in the Total Fertility Rate. Fertility levels declined rapidly between 1970 and 1985. The sex ratio at birth was high during the 1970s, even before the advent of sex-selective technology. This may reflect female infanticide at birth, and not reporting the child as a live birth. Sex-selective technology became widely available by the mid-1980s, and the sex ratio at birth rose sharply until the mid-1990s (Figure 2). Since then it has been declining, but is still well above normal and South Korea remains second only to China in the masculinity of its sex ratio at birth.

It is striking that the sex ratio at birth fell while the Total Fertility Rate plummeted to just above 1 child per woman. Rapid reduction in fertility tends to increase pressure not to have girls ⎯ as the 8