Well I've already mentioned my main reason that cloning is bad, which is that we don't need anymore frickin' people on this planet. I have no problem with an infertile couple wanting kids, so let them adopt.

Another very valid argument is that as we start cloning ourselves, germs and infectious diseases will be able to spread more easily, because the numbers of unique genetic makeups in the gene pool will go down. In the first couple "generations" of clones this wouldn't be as big of a thing, but as the process continues, there will be more and more clones and less and less "real people" who were born of a mother and a father. Sexual reproduction introduces new genetic makeups into the population which, in addition to fostering diversity of people and their traits, makes the overall population less succeptable to mutating diseases.

Furthermore, cloning allows mutated genes and undesirable human traits to persist. No longer is it up to the forces of evolution and natural selection to pick out the traits that shape the human race, now it's up to whoever has the most money to be able to afford the most clones of themselves.

And perhaps most importantly, as genetic diversity declines, clones will be sexually reproducing with other clones, and you will see inbreeding of genetically similar people. As you may know, inbreeding leads to more birth defects, and when those defective clones clone themselves, well... You know.

It's easy to say "yeah, well we'll make sure that clones don't sexually reproduce" but who's going to stop them? The fact is whoever can do something will do something eventually. The same argument works against the hypothesis that we could keep people with serious birth defects/undesirable mutations from cloning themselves. How do you enforce it? The very freedom that allows scientists to try to clone humans would give those clones the freedom to do what they want with this ability.

Are these enough reasons to make you start to think it's not a good idea?