Over the last 160 years, a remarkable decline of fertility has taken place in most European societies. Current below-replacement fertility - i.e. less than two children per woman - has taken such dramatic forms that it looms as the 'key social issue of the twenty-first century'.
Given rapid population aging, European societies are increasingly faced with the question of who will pay the costs of the large and growing group of elderly.
Figure 1. Total fertility rates in Europe, 1850-2006
In explaining family limitation and postponement of childbearing, previous authors have emphasized the effects of industrialization and economic development, the costs of children, and the increasing importance of people's educational and employment careers (Becker 1981; Easterlin 1975). Others have pointed towards ideational factors and cultural change and argue that processes of secularization and individualization are at the root of falling family size (Coale and Watkins 1983; Lesthaeghe 1983). Nevertheless, these explanations, alone or in tandem, have not been able to clarify the large regional differences in fertility levels and reproductive change that have been prevalent and remain existent. For instance, while France pioneered in family limitation already in the eighteenth century, the country was still largely agrarian. Conversely, England, a forerunner of industrialization, retained high levels of fertility until far into the nineteenth century. Presently, southern Europe has the lowest birth rates while in the individualistic Nordic countries, which have high rates of female labor force participation, fertility is substantially higher and even increasing (Myrskylä 2009).
Recently a strong explanatory role has also been attributed to the social relations and interactions that connect individuals to one another (Bongaarts and Watkins 1996; Watkins 1990) focusing particularly on individuals' networks of family and kin. By providing resources and support (Turke 1989; Tymicki 2008) and by passing on preferences and attitudes towards parenthood and childbearing (Axinn et al. 1994; Bernardi 2006; Kohler 2001) family plays an important role in determining people's reproductive behavior. This program builds further on this approach and takes it one step further, namely towards a comparative perspective that explores the channels and mechanisms of family influence on fertility in different cultural contexts. In explaining spatial differences in fertility levels and reproductive change, the program zooms in on the institution where the decisions on family formation and procreation are primarily taken and where the bearing, nourishing and socializing of children takes place: the institution of the family. Individuals and couples deciding on matters of parenthood and childbearing are influenced by spatially and culturally varying norms, values and practices surrounding family and kinship. Clusters of such norms and practices can be viewed as family systems. In different family systems, family and kin affect people's fertility in highly distinctive ways (Das Gupta 1999; Davis 1955; Hajnal 1982; Kertzer 1991; Lorimer 1954; Skinner 1997; Therborn 2004; Todd 1990).
The aim of the research program is to develop a comparative theoretical framework for explaining long-term differences in fertility decline, which merges previous economic and ideational explanations of fertility change with theories on family effects and the cultural variation therein. Novel multi-actor kinship data from historical population registers and contemporary network and survey data in combination with oral history and qualitative sources will - for the first time - offer the opportunity to fully investigate these family effects over the very long term and across a wide range of European societies.