These aren't my ideas, but ponder this... (thanks to Genzo Yamamoto at Wheaton College)
Culture is formed by individuals. All individuals on the planet have two things in common: they are inherent sinners and they are formed in the image of God. These two identities come before identity in Christ. We need to recognize that these two previous identities link us to everyone else. Therefore, individuals create and replicate culture as sinners and images of God. This is a theological framework of culture.
(And I would add brings us all much closer together than we commonly believe...)