The Oppression of Women
Particularly in "Bloodchild", the key theme is Butler's imposition of a female identity on a male character; the narrator, Gan, narrates with a female perspective and he is also impregnated giving him the female's ability to carry a child or an egg as its host. The protagonist is raped, experiences incestuous relationships, and is dominated, which is typically the lot of women in both literature and real life. The enslavement of women to the male gender is the main theme of the story, although it is turned upside down in the way it is presented.
The Power of Fear
In "Amnesty", as well as in the titular story "Bloodchild", one of the primary themes is fear. Sometimes this is fear of something tangible, for example, the fear that the humans in "Amnesty" have of the alien Communities, and sometimes it is fear of something less tangible, for example, the way in which Gan, the protagonist in "Bloodchild", feels exploited and violated, but cannot put his finger on a tangible thing that he is frightened of. His fear is a fear of something intangible that he cannot name.
Butler also uses the theme of fear to show that humans are often afraid of anything they do not immediately recognize or feel familiar with, which is why the humans fear the aliens. They do not look like them and her contention is that humans fear anything that is different.
Alien Invasion and Occupation
Obviously because so many of the stories are about the interaction of humans and aliens, one of the key themes is that of alien invasion, although this is presented slightly differently in that it is the humans who have geographically invaded the homelands and planets of the aliens; however the alien invasion is more of a physical one, in that they are using the humans to act as hosts for their eggs and therefore perpetuate their own race at the expense of others. Throughout the stories the relationship between alien and human is never equal; at best it seems able to achieve a level of symbiosis, but it is generally weighted in favor of the alien.
Slavery and Racial Oppression
Butler's contention that people are afraid of what is different ties in with the theme of slavery and racial oppression in that she uses the way in which humans are afraid of the Communities to show that humans are suspicious of anything they do not immediately see as familiar. She also gives the narrator in "Bloodchild" not just the voice of a woman, but the voice of a black woman, and in this way shows how black women are enslaved and expected to comply with their own oppression by both their own and other cultures.
