Why do our bodies come with so many trade-offs—like back pain, difficult childbirth, or diseases linked to inflammation?

Our newest CARTA series Mismatch: Human Origins and Modern Disease explores how different traits in the human body evolve over time—some as early as 1.5 billion years ago—and how those adaptations continue to affect our health today.

Researchers explain how multicellularity enables the development of organs but also creates the risk of cancer. Our immune system evolves to protect us but can cause harmful inflammation. Breastfeeding supports infant development yet is linked to increased breast cancer risk. And menstruation and highly invasive placentas improve reproductive success—but also introduce new sources of pain and vulnerability.

Human-specific traits come with their own consequences. Walking upright gives us mobility advantages but contributes to spinal stress and childbirth complications. Losing body hair and developing sweat glands helps regulate temperature but makes us more prone to skin cancer. Even our gut microbiome—shaped by our hunter-gatherer diet—struggles to adapt to modern lifestyles, contributing to chronic disease.

Evolution didn’t design us for today’s world. Our bodies reflect solutions to survival problems across vastly different environments and time scales. Understanding these evolutionary mismatches can help us develop better strategies for prevention, treatment, and public health.

Watch the full symposium: Mismatch: Human Origins and Modern Disease.