@Caroline,
I realize that this post is very old and has come a long way, but let's try and bring it home. Let's see if we can find a simple way to answer this question.
The question is "Why does God permit evil?"
Now I'm assuming that by god the OP means an all-knowing and all-powerful supernatural agent that cares for and loves his creatures.
We live in a world where both the just and the unjust alike suffer. Suffering cannot be blamed on humanity alone, because suffering is also caused by other living organisms and inanimate objects. Based on our observations of the world we currently live in, I think we can come to the logical conclusion that such an agent does not exist.