ABSTRACT
This chapter reviews the basic logic of the reproductive process. The proximate determinants of fertility are important precisely because they determine the distributions of the time intervals. Models of birth-interval components therefore provide the most realistic way to mimic the dynamics of the reproductive process. The focus on the proximate determinants can only be justified as a first step toward assessing the effects of more remote influences, which are often of greatest ultimate interest. The proximate-determinants approach can be thought of as an accounting frame within which the precise mechanisms whereby remote influences act upon the reproductive process can be specified. The chapter indicates some of the most active and interesting areas of current research on the remote influences, with an emphasis on biological variables that unapologetically reflects the author's own background and biases. Any diagnostic criteria, including those for detecting undernutrition, must be sensitive and specific.
