中國為控制龐大的人口，自1979年開始實施計劃生育政策，一轉眼已經過了30年，一群1980年前後出生的獨生子女紛紛邁入婚姻、走入家庭，形成了獨生子女相互婚配的「獨生父母」，也同時造就了有別於傳統中國「發散型」家庭結構的「四二一家庭」。 本研究以此為出發，探究「四二一家庭」結構中的新型家庭關係，並挑戰結構功能論大師帕森斯關於現代化家庭之理論。本文認為，由於夫妻雙方皆為獨生子女，父母要協助子女分擔家務不再分身乏術，三代同堂的擴大家庭將成為中國城市的主要家庭模式，並非現代化理論所認為的核心家庭為主；而在四二一家庭中，親子關係也將居於核心地位，有別於帕森斯所認為的以夫妻軸為主。 筆者於2010年5月親赴北京對10位「獨生父母」進行訪談，深入了解獨生子女從擇偶、新婚、一直到四二一家庭成形所遇到的種種情況，包括夫妻家務分工上的不適應、為人父母後的角色轉換，以及在四二一家庭中獨一無二的天倫樂。 本文最後依據中國2010年第六次人口普查結果及獨生父母的訪談內容，結合各方專家意見，對計劃生育政策做出利弊分析，並探究生父母們在邁入家庭、準備「哺乳」的過程中，對父母的依賴，究竟「斷乳」了沒。 / Abstract In order to control the colossal population in China, the Chinese Communist Party have been implementing the birth control policy since 1979.Thirty years on, more and more children born under the one-child policy have arrived at nubile age. Marriage of only sons and only daughters compose the dual-core family which is different from the traditional Chinese family structure. This text focuses on the dual-core family, to explore the new family relationships and to challenge the Modernized theory of family proposed by T. Parsons. The text is of the opinion that the extended family model with three generations will become the main family structure in urban China as opposed to the nuclear family described in the Modernized theory; the focus of the family will be on the parent-child relationship rather than the conjugal relationship Parsons suggested. The author visited Beijing in May 2010 for interviews with ten “only-child parents”, This granted deeper understanding of the range of circumstances encountered during the process of partner selection, marriage and family formation by adult only-children. These include maladaptation in housework allocation, the role switch after becoming parents and the familial relationships and happiness unique to the extended family structure. In summation, the text combined findings from the sixth Chinese national census 2010, the conducted interviews and the opinions of various specialists and scholars to comment on the pros and cons of the birth control policy and to assess the level of parental dependence of adult only-children in China and their readiness for parenthood.