A formal theory for male-preferring stopping rules of childbearing: sex differences in birth order and in the number of siblings.

Through mathematical deductions, this article shows certain macro-demographic consequences of individually employed male-preferring stopping rules in childbearing. It is shown that male-preferring stopping rules generate differences between boys and girls in birth order and in the number of siblings. Two situations are considered regarding the latent probability of having a boy: population homogeneity and population heterogeneity. The sex difference in the number of siblings exists even under population homogeneity, and the difference remains constant when each couple employs a distinct alternative rule. On the other hand, the sex difference in the birth order exists only under population heterogeneity. Substantive implications of these findings are discussed.