Mary O'Brien has inspired a vigorous reexamination of the concept and practices of reproduction. Her philosophy of birth reclaims this central female experience from the existentialist category of unconscious immanence. This article sketches O'Brien's theory and suggests how her reappraisal of reproductive process sheds light on the contradictions in traditional messages about biological difference, the nature of women, and the meaning of motherhood. It illustrates its claim by reading one such message, John Paul II's Mulieris Dignitatem, in light of O'Brien's work, and argues that using the bio-social process of reproduction as an analytic tool helps overcome dualisms and can further feminist insights into incarnation as a dynamic principle of creation. It invites further reflection on embodiment, birth, and motherhood as theological concepts.