Actually, it isn't easier to just clone organs. At this point, we can only build the simplest organs. We've been able to grow skin for a while now, and I seem to remember someone growing a bladder, but I can't think of any other successful organ engineering. Organs form during embryonic development through very complex interactions between cells and tissues and movement of cells that can't be replicated on a single-organ basis. For example, the cell type I study, the neural crest, migrates out of the neural tube (a very early struture that eventually becomes the central nervous system) throughout the embryo. They contribute to several tissues and organs throughout the body. If you tried to grow a heart (for example) from cloned cells, you would be missing the neural crest and part of the heart would not form properly. Much of the current work in this field involves seeding some sort of a matrix with stem cells (which can be obtained from the person the organ is to treat and don't require cloning) and trying to get the stem cells to populate the matrix and build the organ. I believe this is how the bladder I mentioned earlier was grown. In the near term, this approach may work with organs with a simple structure, such as muscle or bone, or perhaps a stomach or liver. On the other hand, through cloning, one could grow an entire organism with all the organs formed properly. Aside from the ethical arguments, we could almost certainly clone a human within the next few years from which we could harvest organs. That is much easier than trying to clone individual organs.
