Margaret Talbot, A Desire to Duplicate newamerica.net
[ backgrounder from almost a couple years ago. Couldn't dig up the original NYT link, but this alternate has the original photos anyway: physics.ohio-state.edu Entertaining but frightening, sort of a common combination these days. Clip: ]
Nearly all of the animal cloning efforts, however, have led to high rates of fetal and neonatal mortality in the resulting offspring. Those who compare cloning to current I.V.F. techniques -- arguing that lots of those fail, too -- neglect to mention that I.V.F. failures consist mostly of unsuccessful implantations, not the sudden deaths of young babies.
"All sorts of things go wrong," said George Seidel, a cloning researcher at Colorado State University. Cloned cattle and sheep are often born dangerously large. "Normally you might expect a 100-pound birthweight in a calf, but with a clone, you might get 160 pounds," said Seidel. Because such outsize calves don't have room to wriggle around in the uterus, they can be born lame or with limb deformities. "Sometimes the kidneys aren't right, they're just plain put together wrong -- or the heart is, or the lungs, or the immune system," he added. "It can be a unique abnormality in each case. They can die within a few days after birth, or sometimes they just can't make it after you cut the umbilical cord." Nobody really knows why.
Only if such problems are surmounted, said Seidel, would experimenting with human cloning be ethical: "We shouldn't be deliberately producing babies with abnormalities. We're talking about an abnormality rate of maybe 30 percent in cloned animals. In human babies, the normal rate of congenital defects is about 2 percent, and we wouldn't tolerate a jump to 3 percent." Indeed, virtually all of the scientists who have tried to clone other mammals say that we don't know enough at this point to try it in humans, and that to do so would amount to hugely risky experimentation on prospective people. Citing such safety concerns (as well as the possible psychological impact on children), the ethics committee of the American Society for Reproductive Medicine issued a report in November saying that cloning as a treatment for infertility did not currently meet "standards of ethical acceptability."
Besides, though cloned animals can be normal and healthy-appearing -- some cloned mice and cattle even seem "improved," in the sense that they appear to age more slowly -- what's normal in a barnyard animal isn't all that high a standard. "The fact that you can get a sheep or a mouse that looks normal," said Stuart Newman, a developmental biologist at New York Medical College, "doesn't mean that some subtle things haven't gone wrong in brain development that you wouldn't necessarily notice in a sheep, but you would in a human. Yes, you can clone a mouse -- but can you take him to the opera?" Cloned humans might show higher rates of cancer or other diseases, but we'd only find out by cloning them and waiting to see if disaster strikes.
None of this means, however, that cloning services won't someday be marketed to desperate people -- or even that human cloning isn't going on somewhere right now. "It's relatively easy to set up a lab and find someone competent to carry out the procedures," warned Roger Gosden, an infertility researcher at McGill University. "Regrettably, we will probably wake up one day to the news that someone, somewhere, has used somatic-nuclear-transfer technology to produce a human clone." |
