This presentation explores the profound cellular relationship that forms between a mother and her child, highlighting the bidirectional exchange of cells and the enduring biological interconnectedness that follows. By examining how this relational biology benefits both mother and child—physiologically, immunologically, and developmentally—Dr. Collier will illuminate a dimension of human life that is at once scientific and deeply relational. Finally, we will consider the broader implications of this mother–child connection for medical practice, for communities of faith reflecting on embodiment and human dignity, and for our understanding of what it means to be human.