The pattern of changing trends and the regional differences in the sex ratio at birth: evidence from Korea and Jilin Province, China.

"The main purpose of this study is to develop explanations for the pattern of recently changing trends and regional differences in the sex ratio at birth in Korea and for Koreans in Jilin Province and Yanbian Autonomous Prefecture, China.... The findings suggest that, since the mid-1980s, sex ratios at birth have risen remarkably in Korea.... This paper also highlights the recent increase in the sex ratio at birth for the Korean population in China, residing in urban areas densely populated with Koreans. As the key forces behind the regional differences in sex ratios at birth, the effects of son-selective reproductive behaviors, which in turn, are affected by the community characteristics, are stressed."