Oryx and Crake by Margaret Atwood is a post-apocalyptic tale that features themes of childhood and manipulation to reveal the horrors of society. Let's look at both of these.
Childhood comes to the forefront first in the Crakers, or Children of Crake, whom Snowman (previously known as Jimmy) cares for in the novel. These creatures are genetically engineered humans who have survived the catastrophe that killed much of the world's population. They are childlike and innocent, comfortable walking around naked. They also seem to be well able to adapt to the post-apocalyptic world in which they live, yet Snowman/Jimmy feels responsible for them and tries to care for them as best he can. These Crakers provide a sharp contrast to Jimmy's own childhood and to the pre-apocalyptic world.
Jimmy's childhood was not especially pleasant. His parents both worked at a place called OrganInc Farms that specialized in artificially growing human organs. His mother became appalled by the work, and this created tension with her husband. She eventually fell into depression and left the family. Jimmy suffered. He lost his innocence, the innocence he now sees in the Crakers, and perhaps this is what compels him to care for the Crakers. He does not want them to be abandoned as he was.
Manipulation stands at the very center of this novel. In the pre-apocalyptic world, scientists were master manipulators. These scientists experimented with human life in unprecedented ways and apparently with full government support. The OrganInc Farms is one prime example as are the genetically engineered Crakers. Further, Jimmy's friend Crake produced BlyssPluss, a pill designed to increase sex drive. But that pill had other results. It made people infertile, and even worse, it eventually killed them. It carried a delayed reaction that released a contagion into people's systems. This was the catastrophe that killed most of the people on earth. Indeed, the scientists who manipulated both the natural world and other people ended up dying along with everyone else.