Germ Line Gene Therapy

Germ cells are those cells found in the ovaries and testes of humans that give rise to sperm and ova. These are the cells that germ-line gene therapy would act upon. The theory is that at a very early stage of an individual's development, perhaps even before conception, changes could be made to a person's genome that would have an effect on every single cell of their body (since all other cells would develop from those early ones) and upon children that they have (and upon all subsequent generations). Any change made to a person's genome using germ-line gene therapy would have long-term, and possibly unpredictable, effects. At the moment, germline gene therapy is not even at an experimental stage, there is a worldwide ban on its development, and ethical debate about its acceptability has been increasing.

Very closely linked to germ-line gene therapy, in fact one might almost call it passive germ-line therapy, is the technique of selective implantation in in vitro fertilization (IVF). This technique does not directly act on the genome like germ-line gene therapy, but produces the same results. By using genetic screening, it is possible for couples undergoing IVF to select embryos to implant which are free from disease genes (for example, if their families have a history of muscular dystrophy). This would produce a child without the gene for that disease, just as germ-line gene therapy would. This technique is already available and being used by some hospitals, yet although there has been ethical discussion of it, it has not really been of the same tenor as that around germline therapy. The point is that if both selective implantation and germ-line therapy produce the same results, are they ethically different, and if they are different, then there must be something ethically significant about directly acting on and manipulating a person's DNA, which is not the case in simple selection.

C. Therapy vs. Enhancement

The final distinction to draw is between genetic technologies used as a form of medical therapy and those same techniques used to enhance the abilities and characteristics that persons already have. For example, gene therapy might be used to increase the height of children with growth hormone deficiency to that of the norm in the population. This would count as therapy. But the same (or similar) techniques could be used to increase the height of a normal child so that they were of above average height. This wouldbe enhancement of characteristics. These possibilities have raised fears of ''designer babies'' and are felt to produce some of the strongest arguments against gene therapy, or specifically, germ-line gene therapy, since the general view is that effective enhancement treatment would have to act on the germ cells.

As the above example suggests, the line between therapy and enhancement is far from clear, and for some this has led to the conclusion that any form of germline therapy, however well intentioned initially, will inevitably lead to the development of enhancement technologies. Such ''slippery slope'' arguments are often used to oppose germ-line therapy as a whole.

Pregnancy Guide

Pregnancy Guide

A Beginner's Guide to Healthy Pregnancy. If you suspect, or know, that you are pregnant, we ho pe you have already visited your doctor. Presuming that you have confirmed your suspicions and that this is your first child, or that you wish to take better care of yourself d uring pregnancy than you did during your other pregnancies; you have come to the right place.

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