The answer depends on several things, one of which is whether you intend to treat the groups as matched (e.g., parent of family 1 = case 1 in parent batch; child of family 1 = case 1 in child batch) or as independent groups. The second depends on whether your sample is really wide enough in terms of parent and child age to permit a traditional covariate treatment of the age variable (or if, instead, there's a huge gap in which no observed cases appear, as would likely be the case if you chose only families with pre-school aged children).
You could use a bootstrap/resampling approach in an ancova or regression framework in order to evaluate scores (on the DV) for differences due to group, and this would offer a viable comparison without having to worry about normality of model residuals. This option is available in a number of statistical programs.