本文根據兒子偏好與家庭資源的理論基礎，嘗試建立一個連續性生育決策的模型，藉由前幾胎子女所組成的手足結構來分析繼續生育下一胎的機率，釐清一系列社會人口等因素的作用。本文分析的資料取自華人家庭動態資料庫（PSFD），樣本出生年涵蓋1934－1986年，藉由這群受訪樣本的資料將能夠獲知其父母親進行生育決策時所考量的因素。本研究的主要發現如下：第一，手足結構的效力獲得證實，影響生育決策的因素不是單個手足成員的效果，而是由各胎子女的性別與出生序組成的手足結構扮演重要角色。第二，性別均衡假設未成立，兒子偏好假設獲支持。在面臨生育第三或第四胎的抉擇時，都是女兒的手足結構，比起都是兒子的手足結構，父母親有較高的機率選擇繼續生育。第三，「偏好生育兒子」與「偏好投資兒子」對生育決策具有相反的影響，隨著生育兒子數目的增加將減緩父母親繼續生育的機率。第四，社會階層假設不成立，不同社經地位的手足結構對生育決策影響力並沒有差異。第五，世代假設同樣不成立，年長與年輕世代的手足結構對生育決策影響力也沒有分別。最後，本研究的結果發現手足結構確實會影響繼續生育的機率，顯示臺灣家庭的生育決策是一種連續性的決策過程。

Drawing from theories of son preference and family resources, this paper attempts to construct a sequential fertility model, and then uses it to estimate the probability of parents' fertility decisions for their first few children by the sibling structure and to elaborate the effects of various socio-demographic factors. The data used in the analysis come from the PSFD, in which respondents were born between 1934 and 1986. The main findings are as follows. Firstly, the sibling structure has a significant effect on fertility decisions. Secondly, the gender-balance hypothesis is rejected, whereas the son-preference hypothesis is supported. Parents with daughters in their first two or three births have a greater likelihood to have a next child. Thirdly, son preference and son investment have opposite effects on fertility decisions. The number of sons tends to reduce the likelihood of parents having another child. Fourthly, the hypothesis of social stratification is rejected. Parents of different status groups make similar fertility decisions. Fifthly, the data didn't support the cohort hypothesis, because the patterns of fertility decisions by different cohorts appear the same. Finally, the significant effect of sibling structure indicates that fertility decisions are made in a sequential decision-making process.