J. XU/REUTERS

Br. Med. J. 338, b1211 (2009)

[1] Zhu, W.X., L. Lu, and T. Hesketh, China's excess males, sex selective abortion, and one child policy: analysis of data from 2005 national intercensus survey. BMJ, 2009. 338: p. b1211.

Analysis of a 2005 census suggests that, in China's under-20 age group, there are almost 33 million more males than there are females.

Therese Hesketh of University College London and her colleagues pin the heightened sex ratio (the number of boys in each age group for every 100 girls) on sex-selected abortions starting with the introduction of low-cost ultrasound in the late 1980s.

The study extrapolates from a survey of nearly 4.8 million people in the under-20 set — covering 1% of this population across all of China's provinces. The authors show the nationwide sex ratio rising from 108 in the late 1980s to 124 in the 2000–2004 period. Male-biased births were highest for rural families who were allowed a second child after having a girl.

/// 貌似问题有些严重，不能等到出现问题去解决。好像大家都意识到这个问题只有改善我们国家的养老保险水平和医疗保险水平，有些问题是一环连一环的，不能把问题留给子孙们。