Butler has won both the prestigious Hugo Award, representing the accolade of her fans, and the Nebula Award, from professional science-fiction writers. She is one of the most literate, sensitive, and imaginative authors in her chosen fields. In Xenogenesis, as in several of her science-fiction novels including Kindred (1979) and Wild Seed (1980), there are important recurrent themes or messages other than her basic strictures against—and depictions of—the devastation of Earthly life as a consequence of human greed, rapacity, and violence. In Xenogenesis, Butler emphasizes, through characterization of her alien race of Oankali, the inexpressible value of all forms of life and the equally vital importance of diversity—not only in regard to biological species but also in regard to racial, sexual, and cultural pluralism. As an African American woman, she perhaps brings particular insights into these issues.

Unlike many traditional science-fiction tales that emphasize hostile alien invasions of Earth, Xenogenesis stresses the vastly superior intelligence and wisdom of the Oankali and the almost benign, patient, and tolerant manner in which they present their proposals for salvaging life on Earth. Despite the near destruction of Lilith Iyapo’s world, it is difficult for her and for others of human origin to adapt to Oankali offers for an extended, disease-free life in a transformed state on Mars or in the Oankali spaceships. To her human eyes, the Oankali— particularly the third sex known as ooloi—are physically hideous, as are their new multipartner mating procedures. Lilith and others must use these procedures to produce hybrid offspring. Almost imperceptibly over time, however, she perceives the beauty of Oankali life-affirming values, understands their incapacity (despite their great potential lethal power) to give pain (for in giving it, they fully share the pain themselves), and comprehends their need to decide by consensus. Butler’s juxtaposing of Oankali ways with the Human Contradiction boldly underscores the weaknesses that have brought such misery into human lives: racial and cultural intolerance, hierarchical divisions, overspecialization, intellectual myopia, the lust for power, and an addiction to violence. As gene traders who evince none of these failings and who ensure their own evolution by breeding with other life-forms, Butler’s Oankali contrast sharply with the ordinarily parochial, Earth-destroying humans.

Xenogenesis consequently functions well at two levels. As straightforward science fiction, it depicts a plausible alien race, replete with ingenious descriptions of its varied appearances, purposes, and technologies. For example, Oankali spaceships are life-forms themselves that feed on everything, recycle everything, and produce no wastes. In this context, Xenogenesis is an engaging adventure story that proceeds across several generations of humans, hybrids, and aliens busily interacting and testing their fortunes between Earth and space. Moreover, there is ample suspense as Butler presents Lilith and her progeny with hard decisions—classic Faustian decisions—about abandoning Earth. The Oankali believe Earth is doomed, so Lilith and her descendants must choose whether to stay on that planet or assume new lives under more propitious (though not human) conditions on Mars or aboard the Oankali’s living spaceships. On a different plane, Butler has written without didacticism a morality tale about the glory and sadness of being human and about improved methods of survival and moral opportunities that one day could be exploited by more open minds and warmer hearts.