Just as the world’s zoos breed critically endangered animals in captivity to repopulate the wild, scientists are building a global effort to freeze corals for reef restoration. Mary Hagedorn Coral ...

For most of human history, reproduction was governed by necessity rather than desire. Children were insurance against disease, labour shortages and early death. Large families were common not because ...

A colony on Mars will fail as a back-up plan after a catastrophe on Earth. It is hard to see how it could repopulate Earth with a significant number of people. Returning to Earth from space is a ...