本主主要討論生育率年齡分佈對出生數量與年齡結構的影響，及此一影響在社會福利政策上的意涵。我們使用1956年到1992年的出生與死亡資料，固定生育率年齡分佈於1956年之型態，以1956年為基體人口代入人口推計程序進行模擬，就其結果與實際人口 (緊縮的分佈)之比較，指出由於過去育齡人口年齡結構偏重於年輕一端，生育緊縮的實際人口，其出生數量乃較固定生育率年齡分佈模擬的結果來得大，反映於下降的生育率趨勢中則有較小的出生數量降幅，同時產生較低的老年依賴比數值，但由於模擬的期間過短，年齡組成的變化很小。 其次以1992年為基楚人口，設立固定與變化(放鬆與緊縮)的生育年齡分佈型態，產生三組人口推計，進一步說明未來生育事年齡分佈的變化在育兒與養老制度財務上之影響。以固定生育率年齡分佈型態的推計結果為比較基礎，設定生育結付數額爵每次21，345元，則生育事年齡分佈所產生的出生數量週期殼果，使生育站付有2億2千萬到1 千7百萬元之間的費動；如果實拖兒童津貼每月3.000元至滿三歲為止，生育率年齡分佈變化產生的週期效果則介於負9千萬到11億元之間;如果實施國民年金每人每月8，500元，生育率年齡分佈變化對國民年金費率的影響相當微小，最多只能使費率下降0.25個百分點，不過可以使費用減少56億元，上述各項數值占總支出的比重雖然不高，但絕對數額仍值得重視。

Based on the cohort component projection, this paper simulates the effects of fertility compression on birth sequence and age composition in Taiwan, and explores the implications for social welfare. As a first step, we fix the fertility schedule on the age, pattern of 1956 while leaving the TFR to shift as it was, simulate the single year of age population groups from 1956 to 1992. It is determined that the projected birth numbers are smaller due to the fertility compression combined with the shifting age composition in the real series. It is also shown that the simulation results in a smaller, though not significant in magnitude, old -age dependency ratio than the real series. As a second step, we subsequently assumed a fixed age pattern of fertility, a compressed pattern and an expanded pattern in a projection of five year of age groups from 1997 to 2097. Given a constant dollar and a base year population at 1992, it is shown that the variation in fertility schedules can bring about a change, ranging from 220 million to 17 million, in total maternity payment of 21,345 NT per live birth, and a change in the range of 1.1billion to -90 million in total child allowance of 3,000 NT per month per head for the first three years after birth, and a change of zero to 5.6 billion in total pension payment of 8,500 NT per month per head.