Xenogenesis, which is also published under the title Lilith's Brood, is a series of three books by Octavia Butler.

Lilith Iyapo is taken from the Earth after she loses her family—her husband and her son—and is kept with the Oankali aliens for hundreds of years. When she wakes up, she's angry. She doesn't want to get to know the Oankali or mate with them. But she's been selected to carry one of the hybrids of humans and Oankali. Lilith is a fighter who resists the Oankali's efforts to mate her with their people—for a time. The Oankali change her by improving her body via her healing and strength. Eventually, though, she agrees to go through with it and tries to eventually convince other humans to work with the Oankali. The changes the Oankali gave her make it more difficult for her to work with them though.

Jdahya is the alien that teaches Lilith what she needs to know and prepares her to carry hybrids. He's an Oankali who looks like a reptile but is a kind and compassionate creature. The Oankali saved the humans who were about to go extinct. They want to repopulate the Earth with hybrids. His son, Nikanj, eventually bonds with Lilith as her mate. Nikanj is an Ooloi. He's able to link mates together and heal certain types of diseases and illnesses. The Oankali believe that creating a hybrid species will allow humans to continue without destroying Earth and each other.

Akin is the son of Lilith and her mates, five beings total. Two are human and three are alien; one of the aliens is an Ooloi. Akin is a human-Oankali hybrid. He's kidnapped by a group of people who oppose the Oankali and don't want to mate with them. The Oankali decide to let him stay with them because they need to decide what to do about the resistance.

Tino is Akin's adopted father. He's a human who doesn't want to mate with an Oankali but does want to be with Lilith. He's a product of his environment. In the village where they live, two hybrid children are kidnapped ,and many villagers want to cut off the parts of them that look alien.

Dichaan is Akin's Oankali parent who wants Akin to know more about his alien side.

Jodah is an Ooloi construct—the first—which means that it can also link mates and heal diseases despite its partial human ancestry. It goes to live in the forest because of its unique makeup. The Ooloi don't have a gender. It meets two humans who are still fertile named Jesusa and Tomas. They're still fertile. Jodah makes them both into his mates.

Aaor is Jodah's sibling and also an Ooloi construct. He isn't mated yet and, like all Ooloi, needs to be.