The commonly held story goes that we all begin life as a single cell in our mother’s womb and go on from there to develop into fully formed adult human beings composed of cells of our own creation. However, recent research is showing that this isn’t quite the full picture. Not all of the cells in our bodies come from this single starting point. We are, in fact, all host to cells that have migrated from the bodies of other people – our mothers, grandmothers, siblings and even, in some cases, complete strangers.

In this episode, we’re joined by science writer Lise Barnéoud to talk about her latest book Hidden Guests - Migrating Cells and How the New Science of Microchimerism Is Redefining Human Identity.

She tells us how mothers and babies share cells across the placenta during pregnancy, how these cells make their homes within our organs and persist for our entire lives, and how this mysterious process led to a woman giving birth to the genetic children of her unborn twin sister.

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