This paper argues that the expectation of having to provide care for aging parents in the future may be a major factor contributing to the current low fertility rate in Japan. Using data from the 1998 and 2008 National Family Research of Japan (NFRJ) surveys and a Poisson-logit hurdle model, this paper examines whether the expectation of having to look after parents in the future affects a couple's current family planning. The first-stage model of a couple's family planning decision is a logit model which examines the decision of whether or not to have any children, and then in the second stage a Poisson model is applied to explain the number of children a couple has conditional on the couple having at least one child. The empirical evidence presented suggests that there are strong generational effects, and that for the post-war cohort, an increase in the probability of having to look after a parent increases the probability of a couple being childless.

本文认为，未来必须为年迈的父母提供照顾的期望可能是导致日本目前低生育率的主要因素。本文使用 1998 年和 2008 年日本国家家庭研究 (NFRJ) 调查的数据和 Poisson-logit 障碍模型，检验了未来必须照顾父母的期望是否会影响一对夫妇当前的计划生育。夫妻计划生育决策的第一阶段模型是logit模型，考察是否要孩子的决定，然后在第二阶段应用泊松模型来解释夫妻有多少孩子。这对夫妇至少有一个孩子。所提供的经验证据表明，存在强烈的代际效应，而对于战后群体而言，