Let me address directly the question of knowledge and doubt. Many Latter-day Saints (including many who have grown up in the church) are now re-examining their faith and are questioning whether or not they really believe the claims of the church to be true. In our information age we have a world of knowledge quite literally at our fingertips, and that has changed the landscape dramatically.
Note: This post was written a few years ago, prior to the Church publishing this essay on Race and Priesthood. I'm still keeping it up here, because I think there's some good things here. But suffice it to say, the landscape has changed somewhat..