S.c.r.e.e.n.i.n.g f.o.r d.e.f.e.c.t.s b.e.f.o.r.e b.i.r.t.h
The number of inherited and congenital disorders that can now be
diagnosed before birth is increasing. This offers a further option for termination of the
unborn child. The original method used in prenatal diagnosis is to punch a needle through
the mother's 
abdomen and extracting a sample of the fluid
surrounding the unborn child. The fetal cells can then be cultured and
investigated. This examination reveals abnomalities such as Down's syndrome and the sex of the child.
This method has now been joined by a technique called chorionic villus sampling. A small piece of placenta, as an embronic tissue, is genetically identical to fetal cells, is snipped off. In this case the embronic tissue can replace the testing of the fluid and it can be done at an earlier stage of pregnency.
The other advance that has brought to this field is the development
of DNA testing by which single gene defects can
be idnetified in fetal cells. Single gene defects may include as many as 5000
types but the most commonly known one is cystic fibrosis. By next century, we may
well be able test for all of them.
It is very possible that all fetuses will be screened for such defects as they are very rare. But this testing also arouses clear moral arguments. Should we avoid the birth of a child with cystic fibrosis? But what about a child who is abnormally intelligent? Or exceptionally tall? How should we measure the degree of a disability or abnormality?
Genetic screening is not confined to unborn children. Most hopefully it will also be provided to would-be parents to confirm any suspicion of inherited diseases. Genetic screening, in one way may help us avoid most of the forseeable diseases, but may also turn out to offer disturbing insights to our future.
Further Readings:
Ultrasound, Amniocentesis, and other Prenatal Diagnostic Tests
Information about
Amniocentesis and Chorionic Villi Sampling