This report compares national distributions based on data from the American Community Survey (ACS) with those based on data from various Census Bureau surveys for two items: fertility (women who gave birth in the past 12 months) and grandparents residing with their grandchildren.  This report first compares estimates of the number of women who gave birth in the 12 months preceding the survey date based on the 2004 ACS with estimates based on the 2004 June Fertility Supplement to the Current Population Survey (CPS).  It then notes variations that are both statistically and substantially different, and for those found, offers possible explanations.