According to the Osmond family they are. At least that's what I heard them say on the Larry King Show on CNN the other night. I hate to be too hard on them, as they mourn the death of their father. But they are deceived by confessing that they are Christians. Mormonism has nothing in common with orthodox Christianity. Click here to see a chart of comparisons on the Christian Apologetics & Research Ministry (CARM) website.
Also, read this article from GetReligion.org. To me, the whole DNA thing should put things to rest. And Pastor Juan Palm has a good question to ask Mormon missionaries: "Why are there no maps in the Book of Mormon?" Compare this with every edition of the Bible, which as you know, has plenty of maps ... pointing to the historical nature of the Bible in distinction to the LDS scriptures.