Over the past 50 years, family formation trajectories have undergone major changes in the events that occur as well as in the timing and order of these events. Whereas previous studies showed when and how these shifts occur, not much research has been conducted to test why these changes have taken place. This paper tests two possible explanations, namely cultural (secularization) and economic (youth unemployment) change using the Fertility and Family survey of the Netherlands conducted in 2008. We also employed a new method, Competing Trajectories Analysis (CTA), which combines features of sequence analysis and event history analysis, to examine the relationship between secularization and youth unemployment and pathways into adulthood. Our results show that the start of family formation is postponed in times of high secularization and youth unemployment, when pathways including early marriage and parenthood become less popular, and cohabiting without having children becomes more popular.