Cloning's Slippery Slope

Sometime in the next two years a human being will likely be cloned. This may or may not bring shudders of horror, but will certainly not occur outside the law or in some shadowy offshore location. The medical, scientific, legal and political establishment will fully support the effort. This clone, however, will never leave the British laboratory in which it was created.

Last January, a form of human cloning called “therapeutic cloning” – or more properly “cell nuclear replacement” – was legalized in Britain. As with in vitro fertilization, the British appear to have been the first to devise a regulatory scheme for morally contentious technology. The world is watching what will happen next.

It is rather like a Woody Allen script, but run backwards. In Allen's 1973 film Sleeper, attempts are made to clone Hitler from his preserved nose. Today, instead of cloning people from spare parts – or spare cells, as is the case with reproductive cloning – scientists hope to grow those parts by cloning people.

The first part of this procedure is similar to that used to create Dolly the sheep, the first cloned mammal. The nucleus from a human cell is inserted into an egg that had its nucleus removed. An embryo forms, but it will not be implanted in a uterus. Instead, embryonic stem cells will be derived from its inner cell mass. These cells have the potential to become every cell-type in the body, a potential which may lead to cures for many chronic diseases. Stem cells cannot become a baby.

While Britain has legalized therapeutic cloning, they are poised to ban reproductive cloning. They oppose projects such as that of Drs. Severino Antinori of Rome and Panayiotis Zavos of Kentucky in America, who plan to enable infertile men to become fathers by inserting their DNA into an egg from their partner.

Reproductive cloning raises several moral issues – principally those of safety. Scientists believe that human clones would have defects. Because the egg that receives the new nucleus has to reprogram it quickly – teaching it to give the instructions necessary to construct an entire human being - genes that should be “turned on” might well be “turned off,” and vice versa.

This probably explains why at least some animal clones have problems with their hearts, lungs, and immune systems. Weight is a problem too. Dolly the sheep – although still going strong five years after her birth, and the mother of six (all conceived the old-fashioned way) – has always been plump. During a trip to the Roslin Institute where Dolly was cloned, I found her, shorn of her fleece and revealing an ample midsection, mournfully staring from behind a sign that said, "hay only." The Duchess of York, Sarah Ferguson is not the only British celebrity on a diet.

Being overweight is obvious. Other defects may be subtler and, perhaps, insignificant for farm animals. But where humans are concerned, safety must come first. Because the defects found in clones are not genetic mutations, pre-implantation diagnosis at the embryo stage will not reveal their existence.

Problems caused by these defects could emerge at any point in the person's life. We would see a greater range of defects than we do in animals like mice because it is easier to analyze human behavior and physiology. Therapeutic cloning would probably be safer than reproductive cloning because any reprogramming defects would not affect every cell in the body – just the cells used in therapy.

Thus far, only the UK has legalized therapeutic cloning. A law passed late last year in Japan permits it but forbids transferring the embryo to the uterus. In March, Denmark’s Council of Ethics endorsed therapeutic cloning. Will any country that legalizes therapeutic cloning inevitably slide down the so-called slippery slope and end up tolerating reproductive cloning?

The idea behind a slippery slope is that if you do x, which is acceptable, you will end up doing y, which is not. Indeed, two types of slippery slopes – logical and sociological – exist. On the logical slippery slope, you slide to the bottom and embrace the morally unacceptable because there is no way to distinguish it from an acceptable practice. You can slide down the sociological slippery slope from one practice to the other – even if the two are conceptually different – just because the existence of one creates a social climate receptive to the other.

Therapeutic cloning is conceptually distinct from reproductive cloning. Although the first step is the same, the intent behind the practices is not. The former would be done in order to save lives by treating diseases now incurable – say, Parkinson's, ALS, and multiple sclerosis. The latter – creating a person by cloning – would be done for reasons extending from egomania, to confusion between replication and resurrection, to the understandable desire to have a biologically related child.

Will therapeutic cloning make it more likely that people come to accept reproductive cloning? I don't think so. Therapeutic cloning is intended to heal the sick. The cells created through cloning would be an extension of the patient: a means to treat him with cells generated by his own body. It’s almost like donating a pint of blood for yourself in case you need it for subsequent surgery.

Even though I do not believe in a slippery slope from therapeutic to reproductive cloning, a society’s laws should give voice to its values. In countries which allow for the former, it is probably a good idea to ban the latter.