An analogy used when fax machines were common to describe a process that gives
diminishing returns. When a document is sent between fax machines, the resulting copy is not perfect. If this copy is itself sent to a fax machine, the resulting copy of that copy is even further from
the original, and so ad
infinitum.
Cloning for countless
generations has rendered these people impotent and hideous, their genetic structure degraded
to the point of near inoperability. The effect on their DNA from the creation of each
new generation of clones was, in essence, like faxing a fax.