If there is one Christian doctrine that I think is deeply pernicious, it is that of original sin. For those unfamiliar with it, it essentially says that the first sin was committed by Adam and Eve when they disobeyed god and ate fruit from the tree of knowledge. This act resulted in them being banished from the Garden of Eden and became the ultimate cause of all the suffering in the world today. Thanks, Adam and Eve!
This doctrine enables believers to avoid the awkward question of why god allows innocent babies to suffer. The answer is that babies are not as innocent as they look because they carry with them original sin. It is also why Christian fundamentalists are so determined to believe in the historicity of Adam and Eve because without them, there would be no reason for Jesus to die to redeem people from that sin. (I know the whole thing makes no sense but stay with me here.)
We see the damaging consequences of this belief that sin is the cause of suffering this story from Bob Jones University (as fundamentalist an institution as you can get) where five women who were raped or sexually assaulted were told that it likely happened because they had somehow sinned in some way. So rather than try and seek justice for them, the school personnel essentially told the women to forgive the person who abused them and to think about what ‘root sin’ they committed that caused the assualt and not do it again. A more blatant case of ‘blaming the victim’ is hard to imagine.
Of course, this also conveniently allowed the school to sweep the problem under the rug and not take any action that might make the news.