The problem is if the clones are conscious...in other words, if it is a being that thinks rationally, experiences emotion, pain, etc, who are we to grow a herd of these things and ultimately submit them to a life of bondage? I guess the question becomes, at what point is a life not a life? A clone may bleed like I do, feel pain like I do, be able to think and act as I do, yet because it is a clone, we can pump his veins full of diseases and let him suffer while we observe the effects? It doesnt sound right.....if the being was nothing more than a bag of tissue that could not think, had no emotions, no pain receptors, essentially a biological robot, then I could see using his carcass for research or slavery or Lord knows what else....but if the being has the traits of humans, then by negating a clone's rights, we are one step closer to negating our own rights.
The problem, as I see it is, what if you woke up one morning and you were stored in a box for 8 hours per day to sleep and then worked 16 hours in some type of task. Then fed, told to strip, hosed off with chemicals to cleanse you, and then placed back in the box for 8 hours.....all the while being conscious of your surroundings and having nothing to look forward to for the rest of your life? If someone is a zombie and neither knows no better nor cares, then perhaps it is a valid existence....but for a man who thinks, it is a living hell...because our entire world has progressed as a result of men thinking.....we have done great things thus far and to reduce a man to nothing more than a mule is the ultimate humiliation regardless of whether he was born of a woman or hatched in beaker.
The real fear that I have is, this issue will become of greater importance within the next 50 years.