Actually it is turning out that cloning is WAY more complicated than people thought. It comes down to gene expression - most noteably female gene expression. See the X chromosome is special - all the information you need is really contained on just one X chromosome - which is why boys can get away with having one X and one Y. So how does the body work out which X chromosome it should be listening to when they have different genes. Answer:- the fetus selectively develops with the majority of cells having one of the X chromosomes "dominant" but it may not be all cells. This explains the "tabby" pattern in female cats. When they cloned a tabby cat the cloned "duaghter" had a different tabby pattern to the mother - reason - different X chromosome expression pattern.
They are starting to believe that this is the reason why more women suffer from autoimmune disoders than men.
Anyway, I still have mixed feelings on this one - I can see the many wonderful medical opportunities and advances on one hand, but don't like the idea of human embryos being used for such. No. I can go with stem cell research, no problem - as in cells used from the umbilical cord, etc. But not cloning embryos - even IF they were just supposed to get "trashed"... it bothers me.
Surely there's a better option?
Hmmm, in the meantime here is a link to lots of articles on cloning.
http://www.newscientist.com/hottopics/cloning/