MIT TECHNOLOGY REVIEW: Genetically optimized babies, new ways to measure aging, and embryo-like structures made from ordinary cells: This issue explores how technology can advance our understanding of the human body— and push its limits.

The race to make the perfect baby is creating an ethical mess

A new field of science claims to be able to predict aesthetic traits, intelligence, and even moral character in embryos. Is this the next step in human evolution or something more dangerous?

The quest to find out how our bodies react to extreme temperatures

Scientists hope to prevent deaths from climate change, but heat and cold are more complicated than we thought.

The astonishing embryo models of Jacob Hanna

Scientists are creating the beginnings of bodies without sperm or eggs. How far should they be allowed to go?

How aging clocks can help us understand why we age—and if we can reverse it

When used correctly, they can help us unpick some of the mysteries of our biology, and our mortality.