New organs for humans can be 1. * Grown in vivo using stem cells 2. * Artificially grown in vitro (in a lab) 3. * Grown in a genetically modified animal (xenotransplantation). 4. * Built as a machine (cyborgisations) Organs can be grown from a few cells "manually" using artificial scaffolding. Or they can be grown inside cloned organisms. The scaffolding may in time be produced using printing based manufacturing, i.e. built up in layers, as this allows precise and custom control of the shape.