Humans, clone themselves to perfection by end of 2100. Clones are in suspended state of life. They are used for harvesting body parts. Slowly Humans become totally de-sensitized to the fact. Whenever a child is born, he or she is cloned using blood from umbilical chord. The clone is kept in lab and fed food. It grows around same time period. Only rich can afford this in the beginning. Some people have multiple clones at various age. This is called "Stepped Cloning". Stepped Cloning is used for harvesting younger parts as the "Owner" grows older.