Who should undergo genetic testing?
So that raises a bunch of questions about genetic testing that I want to touch on. The most obvious, to begin with, is who should be tested. By the way, I need to draw a distinction fairly early on between screening and testing. Testing has to do with individuals. Screening refers to whole populations. There are diseases for which we now screen routinely. An example would be fetal phenylketonuria (PKU) in which virtually every newborn in the developed world is screened, simply because there's a very simple remedy if the kid tests positive for PKU. Dietary changes can prevent the onset of this otherwise terrible disorder. So, screening is effective when it's cheap and when there is something that can be done effectively to remedy the condition.
What about genetic testing of individuals? I think that the consensus that is now emerging is that we shouldn't even begin to think of genetic screening for a whole range of issues and that we should limit testing to those who are in high risk categories. You'll be hearing more about that this afternoon, when you have genetic counselors actually addressing this issue more specifically. I think that what they will be saying is where there is a strong family history of a certain disorder, or in the case of children, previous children in a family that tested positive or later proved to be positive for a disorder, these would provide good reasons for testing further pregnancies or other members of the family. But this should be used with considerable discrimination.