Persistent ageing population is an alarming problem in today?s Europe. Germany as one of the largest economies is also known for its decades? long population ageing due to continuing fertility decline. The dearth of labor force in the market, as a result of the ageing population, demands increasing female participation in the labor market; meanwhile, the persistent fertility decline signifies significant need of new childbirths. Hence, this double-burden progressively alights on women?s shoulders. Moreover, ineffective policies, social constrains and insufficient child care facilities in Germany aggravate women?s incompatibility between motherhood and employment, which become two exclusive alternatives (Kreyenfeld, 2004) for German women. Hence, two polarizing categories appear in German society --- work- oriented and family-dedicated (Hakim, 2006). Based on Fahey and Speder?s (2004) affordability hypothesis and ?mismatch? of people?s preferences and ultimate aspirations, this thesis argues that German women desire to have both children and career, however their preference to do so is quite restricted by incompatibilities of employment and motherhood from social constrains. Based on this argument, this thesis essays to examine how German women?s preferences for childbearing and childrearing is affected by the current social constrains in Germany. This thesis strives to shed light on the linkage between preferences and constrains by a preference- constrain-framework. Due to special historical facts, differentials of fertility development and female labor force participation between West Germany and East Germany are also elaborated. This thesis argues that policy-makers should formulate timely and effectual maneuvers for raising fertility rate as well as encouraging female participation in labor force, based on the connections of people?s preferences and social constrains. This thesis finds out that subsidized high-quality child care is a key solution to amend the fertility rate and female labor participation in the West Germany while appropriate economic support and incentives can help these two issues in the East Germany.