Leviticus 21

God held His priests to a higher standard than He did the rest of the Israelites.  Even though it seems as though God was discriminating against the handicapped Levites in verses 16-23, it was not meant to be that way.  Just like the animals being sacrificed, God needed the priests to be as close to perfect as possible, both in their actions and in physical appearance.  These handicapped priests were not discarded, however, they were taken care of and likely had other duties to fulfill within the tabernacle.