I agree with KenWittlief that it will be the social issues that present the most important engineering problems to future generations, case and point, snuppy.

Snuppy is the first cloned dog, which raises the question not of how far we can go, but how far we should go under certain circumstances. (Dogs are inherently more difficult to clone because their ovulation is influenced differently then most other mammals when the same drugs are used on them). I believe it to be fact that one day we will be able to clone humans, but when we get to that point, the question will be, should we?

My opinion is that scientific progress is never bad, but sometimes the applications can be, and as Ken said, it comes down to human motive, which is our greatest gift and our biggest stumbling block. Not that I'm completely against having an evil clone army to serve me .