B‐cell genesis in the bone marrow declines with advancing age. In this review, we discuss our current understanding of why B‐cell production rates decline with age with a special emphasis on why age‐related factors might target very early lymphoid precursors. We consider the impact of aging on cytokine responsiveness and how current models for lineage relationships for very early B‐ and T‐cell precursors might influence interpretations of experiments addressing age‐associated declines in B‐ and T‐cell differentiation. This discussion centers on the notion that aging affects events associated with the process by which hematopoietic stem cells are guided toward the B‐cell pathway. Finally, we present a model in which the age‐associated loss of early B‐cell precursors is linked to suboptimal function of key transcriptional regulators of very early B‐cell development.