This project is the first comprehensive study of the demographic consequences of a major recent development in Europe: while men have always received more education than women in the past, this gender balance in education has now turned around. For the first time in history, there are more highly educated women than men reaching the reproductive ages and looking for a partner. I expect that this will have profound consequences for the demography of reproduction because mating practices have always implied that men are the majority in higher education. These traditional practices are no longer compatible with the new gender distribution in education. The objective of my project is to study in depth the consequences of this historically new situation for reproductive behaviour. The first step of the project is to reconstruct country-specific time series charting the shifting gender balance in education across time and space at different ages. These can then be used as contextual information in subsequent multilevel analyses of reproductive behaviour. In the second part, I will investigate how the reversal of the gender balance is influencing patterns of assortative mating by level of education. Third, I will study how the shifting gender balance is connected to the timing and probability of marriage versus unmarried cohabitation and to the timing and quantum of fertility. Finally, I will investigate the consequences for divorce and separation. Existing data sources will be used that cover a wide range of European countries. This project will not only be ground breaking by setting the research agenda for a new era in the European reproductive landscape. It will also introduce methodological innovations. First, agent based modelling will be used as a method to study assortative mating. Second, I propose a new way to study the causal effect of the gender balance in education. These methodological innovations will prove useful for many other social science projects.