Lilith eventually bonds to Nikanj, an Ooloi. The Oankali have made Earth habitable and obtain Lilith's help in awakening and training humans to survive on the changed Earth. In exchange, the Oankali want to interbreed with the humans to blend the human and Oankali races, a biological imperative they compare to a human's need to breathe. They perceive the interbreeding as mutually beneficial; in particular, it will solve what the Oankali think is the humans' fatal combination of intelligence and hierarchical tendencies. They are particularly attracted to humans' "talent" for cancer, which they will use to reshape themselves. The humans rebel against Lilith and the proposed "gene trade," and kill Joseph, Lilith's new mate. This group is sent to Earth without her. Nikanj uses Joseph's collected DNA to impregnate Lilith with the first Oankali/human child.