The current decline in family size in Australia has sparked considerable debate. Having children is usually seen as a matter of choice, but external circumstances may place constraints on this choice. What is the impact of relationship status on men's and women's intentions about whether or not to have children? And how do changes in relationship status affect those intentions? Based on data from the Australian Family Formation Project, the analysis in this paper focuses on intentions and outcomes regarding having children, covering nearly a decade. Three issues are examined: the prevalence of intentions to have children or remain childless among men and women when they were first contacted (1981); whether those who did not intend to have children were less likely to change their minds than those who intended to have children; and the extent to which relationship status and changes in relationship status over the next ten years influenced intentions and outcomes.