We apply cohort techniques to monitor four indicators of socio-demographic risk crucial to family wellbeing; namely, income, employment, education, and housing. The data were derived from New Zealand's five-yearly Census for the period 1981-2006. This allowed us to track birth cohorts of mothers (and their families) over six successive New Zealand censuses focusing on the main childrearing ages of 20-59. This produced ten cohorts--termed "open familial cohorts"--ranging from mothers born in the period 1932-1937 through to 1977-1981. We present age, period and cohort analyses. Families in which the mother is in her early 20s were the most vulnerable, with the lowest incomes, the greatest risk of worklessness, and the lowest levels of home ownership. Of particular interest is that those in the most recent cohorts--born since 1967--were worse off compared to earlier cohorts. The period from the mid-1980s to the mid-to-late 1990s was one of greatest "socio-demographic risk", with the lowest work, income and education prospects over the 25 years. The picture on generational profiles was mixed. Contrary to popular mythology the "baby-boomer" cohorts did not enjoy an unqualified advantage over others; indeed the most recent cohorts were doing well, with relatively high incomes, education and work levels. The analysis is successful in identifying age and period effects over a period of major social change, and in documenting cohort experiences for each indicator, thus demonstrating the potential of constructing cohorts from routinely-collected census micro-data for monitoring and policy purposes.