中国双生子出生的人口学特征研究

A Study on the Demographic Features of Twin Birth in China

双生子出生是普遍存在的小概率生育事件，双生子研究逐步受到人口学界的重视。本文利用第四次全国人口普查资料中的生育数据分析双生子出生的人口学特征，并与单胎生育特点进行比较。研究表明，1989年中国育龄妇女的一般生育率为78．83％o，双胎出生率为7．81％o。虽然生育率和双胎出生率都与女性生育年龄和所处的社会经济状况有关，但两者具有不同的特点和随年龄变化模式，属于两种不同的生育事件，双胎出生率在妇女30。34岁以前随着生育年龄的升高而上升，并且主要是由增加异性双生子对与同性双生子对的比例贡献的。

For twin birth is a small probability fertility event, studies on twins have been growing to be paid attention by demographic fields. This paper utilizes the fertility data from the firth Census to study the demo- graphic features of twin births in China in 1989, and compare them with that of single births. The results show that the general fertility rate was 78.83%0, twin birth rate was 7.81%o in China in 1989. Though fertili- ty rate and twin birth rate were influenced by fertility age and female social and economic status, as two dif- ferent fertility events, the both had different features and changing models with fertility age. Twin birth rate increased with the rise of maternal fertility age before 30-34, which was owed to the increase of the propor- tion of opposite sex twin pairs to same sex twin pairs.