Fair & false analogie

To compare the human heart with a pump is a fair analogy, as this is essentially the function of the heart i.e. to move blood around the circulatory system via arteries & veins.

To suggest that cloning humans is dangerous and could lead to the production of a Frankenstein's monster is a false argument because if we clone a sheep we get a sheep which is exactly the same.
Cloning may or may not be a good thing but arguments against it must be based on fair analogies & sound logical argument, not scare-mongering.