The number of children desired by individuals-often referred to as fam
ily size desires or preferences-is a central construct in much researc
h designed to understand and predict fertility. It is often used as a
proxy for the construct of childbearing motivation. This paper present
s a theoretical framework that organizes and elucidates the relationsh
ip between these two constructs. That relationship is examined using a
reliable, valid measure of childbearing motivation and data from 195
husbands and 196 wives with no children and 196 husbands and 196 wives
with one child. The results indicate that childbearing motivation has
a complex relationship with child-number desires, characterized by cu
rvilinearity and a failure to distinguish among those desiring more th
an two children. We discuss the implications of this pattern.