Scientists seeking ways to produce enhanced size, strength, intelligence, or resistance to toxic substances are being accused of "playing God."
GENETIC ENGINEERING involves directly altering the genetic structure of an organism to provide it with traits deemed useful or desirable by those doing the altering. Genetic engineering of plants and animals has been going on since the 1970s, though attempts to introduce such traits through selective breeding has been going on for centuries.
The most straightforward use of genetic engineering involves producing a plant or animal with "improved" characteristics. In the case of agriculture, for example, genetic engineering has produced crop plants resistant to lower temperatures, herbicides, and insect attack, as well as tomatoes with a longer shelf life. A completely different type of genetic engineering involves transplanting a gene, usually human, from one species to another in order to produce a useful product. A patent already has been applied for to mix human embryo cells with those from a monkey or ape to create an animal that might have kidneys or a liver more suitable for transplantation to human beings. There seem to be no limits to the creatures made possible by genetic engineering--e.g., creating edible birds and mammals with minimal brain functions, including no consciousness, so as to avoid protests about the cruelty involved in raising and killing conscious animals for food.
Although particular instances of genetic engineering of plants and animals have caused some controversy, mostly because of environmental or health concerns, genetic engineering is a generally accepted practice. The major moral controversy concerns whether to allow directly altering the genetic structure of human beings. Genetic engineering done by altering the somatic cells of an individual in order to cure genetic and non-genetic diseases has not been controversial. Indeed, what is known as somatic cell gene therapy is becoming a standard method for treating both kinds of diseases. Unlike the genetic engineering used in plants and animals, somatic cell gene therapy alters only the genetic structure of the individual who receives it; the altered genetic structure is not passed on to that individual's offspring. However, now that large mammals such as cows and sheep can be cloned, it may be possible that genetic engineering done by altering somatic cells in human beings may be passed on to future generations of human beings.
Presently, somatic cell genetic engineering is limited to therapy--there has not even been a proposal to use it for enhancement. Clinical trials using human patients have demonstrated the feasibility of somatic cell gene therapy in humans, successfully correcting genetic defects in a large number of cell types. In principle, there is no important moral distinction between injecting insulin into a diabetic's leg and injecting the insulin gene into a diabetic's cells.
The most serious moral controversy concerns the application to human beings of the kind of genetic engineering used on plants and animals. This type of human genetic engineering, usually referred to as germ line gene therapy, is regarded by some as the best means to correct severe hereditary defects such as thalassemia, severe combined immune deficiency, or cystic fibrosis. Many believe, though, that genetic engineering to treat or eliminate serious genetic disorders--the practice of negative eugenics--will lead to the process being directed toward enhancing or improving humans, or positive eugenics. This slippery slope argument presupposes that there is something morally unacceptable about positive eugenics, but that has not been No one yet has provided a strong argument demonstrating that genetic engineering to produce enhanced size, strength, intelligence, or increased resistance to toxic substances is morally problematic.
Eugenics properly has a bad connotation because, prior to the possibility of genetic engineering, eugenics only could be practiced by preventing those who were regarded as having undesirable traits from reproducing. …