Some causes can be defined easily by its relationship to the other. You can see this with the pro-life and pro-choice movements. Causes can register themselves as mirroring another cause out there. Then as people are going through the DYC test, they can try to find causes opposite another. (This is different than saying what they’re not interested in. In this instance, they are interested – just in the opposite direction!)
Note that not all of these are controversial. An orphanage and an adoption agency might be linked to mirror causes. One helps children who don’t have parents. One helps parents who don’t have children.