Sir David Attenborough investigates whether the world is heading for a population crisis. While much of the projected growth in human population is likely to come from the developing world, it is the lifestyle enjoyed by many in the West that has the most impact on the planet. Sir David examines whether it is the duty of individuals to commit not only to smaller families, but to change the way they live for the sake of humanity and planet Earth.

Technology is evolving from an external tool we wield when needed to an always-there presence that is with us, on us, even inside of us. As we become more and more wired, are we becoming digital devices ourselves? In this episode meet a Swedish mom who implanted an RFID chip as a lifestyle choice; a filmmaker who lost his eye in a gun accident and replaced it with a camera; and the so-called "world most connected man," who uses between 300-700 tracking and life logging systems to monitor every aspect of his life.