中文摘要：

出生性别比一直是政府和学术界关注的焦点。利用2014年湖北省单独家庭调查数据,实证分析了单独二孩政策对出生性别比的影响效应。限制性生育政策下单独家庭一孩出生性别比失调严重;单独二孩政策的放开,该政策可通过＂释放效应＂和＂稀释效应＂促进出生性别比的平衡;且这一政策效果必须要求这两种效应同时存在,缺一不可。在我国当前低生育率的背景下,政府有必要逐步全面放开二孩,以有效解决性别比失调带来的社会问题。

英文摘要：

Sex Ratio at Birth has been the focus of the government and academia. This paper analyzes the effects New Two- children Policy has on the Sex Ratio at Birth by using the survey data for single households in Hubei Province in 2014, We find that restrictive fertility policy can make the Sex Ratio at Birth imbalanced. With the opening of New Two -children Policy, it is the Release Effect and Dilutive Effect that contribute to the balance of the sex ratio at Birth; what＇ s more, the policy effect must requires existence of the two effects at the same time. The policy implication based on this paper is that under the background of the current low fertility in our country, the government can implement Two - child Policy gradually, which can benefit to solving the social problem resulted from the disorder of Sex Ratio at Birth.