Medicine's last frontier - ethics of genetic engineering - Brief Article

New technology making it possible to produce children immune to chronic genetic disease also paves the way for 'designer babies' for parents who can afford them. This prospect is opening a Pandora's box of ethical, social and legal dilemmas - nowhere more than in the United States.

Boston, USA: June 1, 2010

Barbara is nursing her new-born baby, Max. "My husband and I chose him from the embryos we made," she tells a friend. "We also made sure that Max wouldn't turn out to be fat like my brother Tom or addicted to alcohol like my husband's sister."

Seattle: March 15, 2050

Melissa is in the early stages of labour in a maternity ward. To take her mind off the contractions, she looks at computer-generated pictures of a five-year-old girl with blond hair and green eyes and others of the same girl as a teenager. This is Melissa's yet-to-be-born child. What cannot be seen is that she has a package of genes to provide her with lifelong resistance to HIV infection.

Washington, DC: May 15, 2350

The country is divided into two classes: the GenRich, whose families invested heavily in the genetic design of their offspring, and the Naturals, whose families couldn't afford to do so. The GenRich make up 10 per cent of the population, and dominate the upper echelons of society, while the Naturals work as low-paid service providers. GenRich parents pressure their children not to dilute their expensive genetic endowment by marrying Naturals.

This is not an exercise in Hollywood screen-writing. These scenarios emerge from our current base of scientific and technological knowledge.

Since the 1980s, genetic engineering has been successfully practised with mice, cows, sheep and pigs. It hasn't yet been applied to human beings simply because the most basic technique for adding genes to embryos has a success rate of only 50 per cent at best. And for the even more complicated task of altering genes to cure disease, the odds are about a million to one.

But with cloning, the entire equation changes. You can now take a cell from a fertilized egg of just a few days and then clone it to make millions of copies which could then be engineered by, for example, injecting foreign DNA through a microscopic needle. Thanks to the "Wilmut technique" (see page 21), the scientist can then take a properly engineered cell's nucleus and insert it into a fresh egg which is placed in the mother's womb.

This is just one of many approaches now being developed in laboratories. By using one or a combination of them, genetic engineering of human embryos will be safe and efficient by the middle of the 21 st century. We will face the ultimate frontier in medicine and philosophy - the power to change the nature of the human species.

Genetic engineering will begin in a thoroughly acceptable manner, by treating severe childhood diseases like cystic fibrosis. Services will then steadily expand in two distinct phases. In the first, parents will give their children genes that others naturally have. For example, they will incorporate within their embryos the genes which make some people naturally resistant to certain forms of cancer or HIV infection (about one per cent of the American male population has a gene making them immune to HIV infection). At the same time, they may reverse predisposition to conditions like obesity or alcoholism and diseases like diabetes.

Geneticists will then focus on the mind and senses. To begin with, doctors will replace or alter genes linked to mental diseases and antisocial behaviour like extreme aggression. As technology improves and spreads, parents will have the choice of enhancing artistic potential, for example, by heightening visual or auditory acuity. With better understanding of the human brain, we will enhance cognitive abilities by, for example, strengthening the gene responsible for converting short term memory into long term memory. This is now being done in mice.

All of these services involve altering or adding genes which already exist in the human genome. However, in the second phase of genetic engineering, we will actually introduce new genes into the genome. Humans might develop night vision by gene-transfers from bats or entirely new traits like the ability to decipher radio waves. Obviously, this kind of engineering will take a great deal of time to develop because of the complexity and risks involved. We cannot introduce a gene into the human genome without being certain that it won't cause any harm.

One way or another, we will see an exponential rise in the number and variety of possible genetic extensions - like the additions to computer operating systems that occurred during the 1980s and 1990s. Extensions that were once unimaginable will become indispensable . . . to those parents who can afford them.

Lee M. Silver, Professor at Princeton University in the Departments of Molecular Biology, Ecology and Evolutionary Biology and in the Woodrow Wilson School of Public and International Affairs. Prof. Silver is the author of Remaking Eden: Cloning and Beyond in a Brave New World, Avon Books, New York, 1998.

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