In the novel, families are only allowed to have two children. A third child is considered illegal, so the government forcefully sterilizes women after their second births. If any woman accidentally becomes pregnant a third time, she is required to abort her child.
So, the government intimidates families like Luke's by employing draconian laws to compel implicit obedience. As a means of preventing overpopulation, the government uses the Population Law to decide the size of families; to ensure unquestioning obedience, the Population Police are allowed to use violent measures against citizens. Illegal third children are called shadow children, and the police are allowed to kill them on sight.
In the story, Jen and the other shadow children are brutally murdered by the police for daring to protest the government's stance on population control.
Additionally, the government has also outlawed gender selection procedures; it claims that the drastic law is needed to prevent citizens from destabilizing the population. In the story, Jen confides in Luke that her mother and step-father secretly paid doctors large sums of money to ensure that she would be born female. Any gender selection procedures have to be done secretly so as to escape the detection of the Population Police.
The government even controls what citizens eat. For example, no one is allowed to consume soda or potato chips, snacks the government considers junk food. In the story, Jen tells Luke that the government outlawed junk food by shutting down the factories that produced them. Essentially, only healthy food that can sustain an optimum population is allowed. Additionally, farmers are also forced to move to land that can sustain greater agricultural output.