To make a clone, scientists first take an egg and remove all of its genetic material. Then the nucleus of a cell -- any cell in the body -- is taken from the individual to be cloned and inserted into the hollowed-out egg.

The cell is then given a jolt of electricity or put in a chemical bath to activate cell division -- essentially tricking the cell into doing what a fertilized egg would normally do. Then the embryo is implanted into a woman's uterus who carries the baby to term. Boisselier said the next clone is expected to be born next week in northern Europe, and three other cloned human babies should be born by early February.