In this paper, we generalize the notion of Pareto efficiency to make it applicable to
environments with endogenous populations. Two efficiency concepts are proposed:℘‐
efficiency and 𝒜‐efficiency. The two concepts differ in how they treat potential agents that
are not born. We show that these concepts are closely related to the notion of Pareto
efficiency when fertility is exogenous. We prove a version of the first welfare theorem for
Barro–Becker type fertility choice models and discuss how this result can be generalized …

Fertility rates are declining in many countries. But are fertility rates inefficiently low? This
paper addresses this question by exploring the efficiency properties of equilibria in an
overlapping generations setting with endogenous fertility and dynastic parental altruism,
using the notion of‐efficiency proposed by Golosov, Jones and Tertilt (2007). In contrast to
Schoonbroodt and Tertilt (2014), who show that any equilibrium for which nonnegativity
constraints on intergenerational transfers are binding is‐inefficient (and, under the …