The next frontier in technology is inside our own bodies. Synthetic biology will revolutionize how we define family, how we identify disease and treat aging, where we make our homes, and how we nourish ourselves. This fast-growing field—which uses computers to modify or rewrite genetic code—has created revolutionary, groundbreaking solutions such as the mRNA COVID vaccines, IVF, and lab-grown hamburger that tastes like the real thing. It gives us options to deal with existential threats: