This paper develops hypotheses about the effects of husbands' and wive
s' religious affiliations on fertility. The hypotheses are based on tw
o central ideas. First, religions differ in their fertility norms and
corresponding tradeoffs between the quality and quantity of children;
differences in religious beliefs between husband and wife may thus lea
d to conflict regarding fertility decisions and possible resolution th
rough bargaining. Second, a low level of religious compatibility betwe
en the spouses may raise the expected probability of marital dissoluti
on and thereby decrease the optimal amount of investments in spouse-sp
ecific human capital. Analyses of data from the 1987-1988 National Sur
vey of Families and Households conducted in the United States suggest
that both of these effects play important roles in explaining the obse
rved linkages between the religious composition of unions and fertilit
y behavior.