中国双生子出生性别比研究

人口自然出生性别比是分析和评价人口出生性别比偏离的重要指标,中国对人口自然出生性别比的研究一直比较缺乏。人的出生性别比正常范围为102～107,国内一般都是以其上限作为标准判断人口出生性别比偏高的程度。但是这种做法是值得商榷的。利用第四次全国人口普查资料中的双生子信息探讨双生子出生性别比特征。研究表明,中国1989年双生子出生性别比为104.87,在女性主要生育年龄阶段生育的双生子出生性别比是相当稳定的,比较接近自然状态下的出生性别比。相比较而言,中国人口出生性别比不仅普遍偏高,而且随女性生育年龄变化的模式也不相同。

Studies on Sex Ratio of Twins at Birth in Chinese Population

The natural sex ratio at birth is an important index that may be used to analyze and appreciate the deviation of sex ratio at birth.It lacks of research on the natural sex ratio at birth in Chinese population,scholars usually take the upper limit of the normal range of sex ratio at birth as criteria to judge the deviation of sex ratio at birth,but this method is questionable.This paper utilizes the twins data from the firth Census to study the features of China’s sex ratio at birth of twins born in 1989.The results show that China’s sex ratio of twins at birth in 1989 is 104.87,and remains relatively stable in most maternal bearing age groups.It suggests that China’s sex ratio of twins at birth is near the natural sex ratio at birth.Compared with the sex ratio of twins at birth,the sex ratio at birth in Chinese population remained generally higher at almost maternal bearing ages,and showed different changing model with maternal bearing age.