The relationship between family social background and risks of problems in the areas of health, education, behaviour and offending was examined in a birth cohort of New Zealand children studied to the age of 11 years. The analysis showed the presence of small consistent correlations between family social background and individual outcomes on a range of childhood measures. These correlations ranged from 0.12 to 0.31 with a median value of 0.18. The association between family social background and childhood outcomes was modelled using LISREL modelling methods which assumed that this association was mediated by common non-observed vulnerability processes. This analysis suggested that while variations in family social background act as relatively weak determinants of specific problem outcomes, these factors had a relatively strong influence on the child's generalized vulnerability to a wide range of childhood problems. The implications of these results for research into social background and childhood are discussed.