Did you know your body is never truly sterile—even before you’re born? From semen and placenta to umbilical cord blood, your microbial journey begins early on. And it doesn’t stop there. The type of birth, nurturing, and how you explore the world as a child play a crucial role in shaping your unique microbiome. The introduction of solid foods, interactions with your environment, and social contact add even more layers of complexity. By adulthood, your gut microbiome reaches its peak flexibility and resilience—but its foundations are built much earlier in life.

As a young child, you explore the world with your hands, mouth, and curiosity—interacting constantly with an invisible universe of microbes. However, science has only recently started to seriously explore the deep and complex relationships between children and microbes.

One pioneering initiative is the Microbial Childhood Collaboratory—an international, interdisciplinary research group exploring the concept of the biosocial child: not merely as an individual, but as an ecological being, deeply entangled in microbial and biospheric communities that sustain life. One of their projects, Microbial Childhood: Restor(y)ing Daycare Ecologies, emerges from research and experimentation around the design of a microbial-friendly daycare in Tampere, Finland.

The Collaboratory brings together community artists, environmental ecologists, sociologists, anthropologists, and early childhood education researchers—including Zsuzsa Millei, Professor of Early Childhood Education at Tampere University, who joins us in this episode.