Fertility, Children, and Parenthood
This film centers on an infertility crisis that has plagued humanity for twenty years. People are forced to watch and wait as their population ages, leaving the world completely void of children. The film explores potent themes of the miracle and heartbreak of parenthood—as evidenced by Kee's giving birth to a baby girl, and Theo losing his baby boy to sickness—as well as the innocence and importance of childhood, stressed by the bleak terror of a world without children.
Hope
Though the world grows more and more desolate with each passing day, the characters in Children of Men never lose hope. Much of this hope comes from Kee, whose miraculous pregnancy means that humanity may not face extinction after all. Refugees come to the UK in the hope that, at some point, life will turn around for them. Hope keeps all of these characters moving forward, and the film even ends on a hopeful note, with the Tomorrow approaching and the sound of children's laughter.
Fear
Following the infertility crisis, the totalitarian government in charge of the UK rules by fear. Fear is powerful in its ability to keep people in line and turn their views in a certain direction. In this case, the government is able to foster a deep fear of immigrants and foreigners that brings about the inhumane treatment of refugees in camps such as Bexhill. Fear is a powerful motivator and an unsettling political tactic.
Redemption
Following his son's death to the flu epidemic twenty years before, Theo ceased his attempts at activism and grew apathetic, unconvinced that any effort on his part would change the direction in which his nation appeared to be moving. Theo agrees to escort Kee to the coast not because of the monetary award, but because he feels this is his chance at redemption, his chance to do something he truly believes is right and make a difference. Kee's naming her baby after his own son is confirmation that he has succeeded.
Sacrifice
In a world like the one in Children of Men, sacrifice is often necessary in order to achieve progress. In the film, characters repeatedly sacrifice themselves to protect Kee, believing that she and her baby provide hope for a better future for all of humanity. Miriam stays by Kee's side throughout the journey, and even sacrifices herself to the guards in order to distract them from Kee's contractions. Marichka sacrifices her safety to protect Kee from Syd and get her and her baby to a boat. Both Julian and Theo sacrifice their lives in their attempt to bring Kee to the Human Project. These sacrifices are exemplary in that they remind audiences that humanity is still capable of the greatest good: selflessness.
Faith and Religion
Faith plays an important role in this film. People have often believed that it is God—or an equivalent higher power—that brings life and fertility, so in the absence of this, many believe that God is punishing them in some way. People resort to extreme measures to try and gain God's forgiveness. However, Kee's miraculous pregnancy reminds audience that faith can exist in many forms, and that there is always some reason to keep faith even in the darkest times.
Survival and Human Nature
Although times of trouble often bring out the best in humanity, as evidenced by the many sacrifices made to save Kee, they also bring out the worst. At the core of human nature is the desire for survival, and when people believe their lives are in danger, they will stop at nothing to preserve their lives. This mentality drives the Britons' hatred of the fugees; they have been led to believe that the fugees directly threaten their safety, and thus have lashed out at them in whatever ways they can.
