Most scientists agreed that cloning an entire human being-besides morally
questionable-was filled with technical problems. After all, research into animal cloning
has already shown that there are hundreds of failures, includingmanybadlydeformed
(畸形的)creatures that were usually miscarried.
     Now comes word that it might be easier to clone humans than was previously
believed. People have a genetic quirk(怪癖) that might prevent some of the
developmental deformities associated with animal cloning. One gene, called IGF2R,
is normally imprinted in sheep, cows and mice but not in humans. Human clones would
always inherit non-imprinted IGF2R genes, so there would be no chance of a mix-up
and, their growth would be normal. But what of the other 49 0r so imprinted genes
(遗传基因 ) ?No one knows what troublethey might cause. So the fact humans have
one less imprinted gene than mice, sheep or cows means that human
cloningmightbemarginally (轻微地 ,很少地 ) easier , but not necessarily safer.