Each state has the power to establish its own policy and laws relating to c
hild custody determination. The number of single-parent families with child
ren that are headed by fathers has been growing in the United States. This
paper explores the extent of cross-state variation in the prevalence in fat
her-only families in 1990, and the extent Co which there was cross-state va
riation in the increase in father-only families in the 1980s. The 1980 and
1990 Public Use Microdata Samples (PUMS) drawn from the US decennial census
es are used. Decomposition analyses of growth indicate that increases in th
e number of father-only families occurred across all states during this per
iod, but at varying rates. The primary reason for the increase in most stat
es is an increase in the proportion of ever-married single-parent families
that are headed by a father. It is for these families that are headed by di
vorced or separated parents that state policy relating to child custody det
ermination is most relevant.