Prevailing low fertility rates in several European states, such as Germany, have been studied widely in recent years. Findings include discrepancies between fertility preference and actual family size as well as between fertility intentions and fertility behavior; an ‘unmet need’ for children found on the individual and the societal level. Fertility preference is specified as the individual ideal number of children, and fertility intentions as the long- or short-term plans to have a child. Apart from investigating the rates of realization, these measures have been understudied. The objective of this study is to illuminate a new angle of low fertility rates in Germany by reviewing fertility measures previously considered to be stable predictors of fertility behavior. The aim is to investigate the stability of fertility preferences and of positive short-term fertility intentions of Germans in their reproductive age. According to the Theory of Planned Behavior and the life-course perspective, attitudes and experiences can influence fertility preferences and short-term fertility intentions. In this study, the suspected connection between unstable preferences and intentions and certain attitudes towards and experiences with the career, working life, and childcare situation is examined. These processes are expected to differ between men and women, and between childless individuals, parents with one child and parents with more than one child. Using data from seven survey waves of the German family panel pairfam, fixed-effects and random-effects regression models are run separately for women and men and for those of different parities. The results suggest that those with high career importance and those who expect or perceive a negative effect of children on the career are more likely to have unstable positive intentions. Although fertility preferences are shown to be somewhat unstable, no relevant relationships can be found. The differences between the findings on men and women regarding relevant determinants and direction of the relationships are unexpectedly small. Childless individuals are as likely to hold unstable preferences and intentions as parents.