Genetic Screening

Simon Schaefer

Copyright 1998


Current research from the human genome project has identified numerous genes that are responsible for genetic disorders impacting society. This knowledge provides us with opportunities to test children and adults to predetermine genetic disorders/diseases and make educated decisions about options available. The U.S. Congress' Office of Technology Assessment (OTA) defines genetic testing as "the use of specific assays to determine the genetic status of individuals already suspected to be at high risk for a particular inherited condition." In contrast, genetic screening is defined as the systematic search of populations for persons with latent, early, or asymptomatic disease and is distinguished from genetic testing by its target population (McCarrick, 1997).

The impact that this information could have on society is overwhelming. Once genetically at-risk individuals are identified, they could enter special prevention programs that would provide treatments and information to improve their quality of life (Eng, 1997). A stumbling block in advancing genetic screening technology and implementation is that the majority of inherited diseases are caused by mutations scattered along the length of their respected genes. This has created a challenge for researchers to develop methods that look at a 'big picture' instead of focusing on only one area.

Technical Aspects

Applying this technology is the new challenge facing society. Tests have been developed for numerous disorders and their evaluation is critical to their effectiveness. An evaluation of any screening test depends on three factors, specifically the prior probability of having the condition, the sensitivity of the test, and the specificity of the test (Warmuth, et al. 1997).

Prenatal Testing

Genetic screening and testing have found increasing usage in prenatal care. The tests are performed on pregnant women to provide information on the health of the fetus. In the case that an actual fetal disability is revealed, the mother is confronted with an array of complex decisions, such as to continue the pregnancy and prepare for the birth, fetal surgery or organ donation, or to end the pregnancy with an abortion. There has also been discussion into testing parents who participate in an in vitro fertilization program and are at genetic risk. Testing of preimplanted embryos might ensure that only embryos free of genetic diseases or problems be placed into the uterus.

The majority of prenatal tests involve obtaining a sample of either amnionic fluid, chorion, fetal blood or mother's blood. Not all techniques are invasive though and one example is fetal ultrasound (sonography). This technique is composed of ultilizing sound waves by placement of a transducer, either on the woman's abdomen or inserted vaginally, to obtain a picture of the fetus on a television-like screen. Ultrasound provides a 'window to the womb' and can be used throughout pregnancy for many reasons, including pregnancy confirmation, fetal examination at different stages of development and position of the placenta and other internal organs (Blatt, 1996).

Amniocentesis is a surgical procedure used for prenatal genetic diagnosis. It involves the insertion of a needle into a pregnant woman's uterus in order to remove a sample of amniotic fluid. The fluid contains cells and substances shed by the fetus that can be analyzed in special labs to determine the genetic status of the fetus. Amniocentesis is generally performed between 16 and 18 weeks of pregnancy with a fetal loss rate estimated to be about 0.25-0.5 percent (Blatt, 1996).

Carrier Screening Tests

Carrier screening identifies individuals with a gene that may cause problems for their children or themselves. A test of blood or tissue samples can indicate changes in chromosomes, or changes in DNA that may have been inherited in asymptomatic individuals. These tests can be offered to individuals from specific ethnic groups who have a higher than normal chance of the particular condition appearing in the family. Examples include screening for sickle-cell anemia in Blacks and Cape Verdeans; Tay-Sachs in Jewish persons of Eastern European ancestry; and Thalassemia in people of Mediterranean and SE Asian descent (Blatt, 1996).

A major advancement into the idea of carrier testing occurred in 1994 when BRAC1, the first hereditary breast cancer susceptibility gene, was isolated. Mutations in this gene are associated with breast cancer at an earlier age than that seen in the general population and are thought to be responsible for approximately half of all inherited breast cancer (Warmuth, et al. 1997). The gene is quite large and over 100 distinct mutations have been detected throughout the coding sequence. Because of the large gene size and number of different mutations, genetic testing has been very difficult.

Public Policy Debates

Employee Testing

Few issues in employment have generated as much controversy as employee genetic testing. These tests identify the presence of genetic disorders in healthy workers that may place them at risk for developing certain work related injuries or diseases. Employers could use genetic testing information to ensure workers are not placed in environments that could cause them harm. Workers could also avoid certain work environments that would be hazardous to their health, saving families the physical, emotional, and financial costs of disabling diseases and premature death (Read My Genes, WWW). The major issue concerning screening is that the information gained may be used to discriminate against individuals based on the results of their test. A closer look at the supporting and opposing views will help our evaluation.


Supporters of genetic screening argue that it does not violate the rights of the employee, but rather allows them to make a more informed decision concerning their situation. Employers also have an interest in maintaining a healthy and productive workforce and could use genetic testing to accomplish this. Others hold the idea that all workers have the right to safe working conditions and employers should require testing. The difficulty in dealing with this issue is that both sides make very valid arguments from their perspective.


It appears that the arguments against genetic testing of employees are strongly based on the fact that genetic screening is relatively new and many questions remain to be answered. People in opposition base their differences on the idea that this new power of information will be used in such a way as to discriminate against workers. Genetic testing will brand certain individuals as 'defective' and make it difficult for them to find work.

They contend that while a person's skills, knowledge, or experience are relevant in deciding whether a person is qualified for a job, their genetic traits are not. Further arguments suggest that it would be unjust to receive differential treatment on the basis of genetics, which are fixed characteristics. Some ethnic groups are also more susceptible to certain disorders, which would then represent a form of discrimination by employers.

Opponents also contend that the psychological effects of genetic information can be very powerful. The burden of knowing that you have inherited a fatal disease, that has no cure, could be devastating to the individual and/or family. What would be the purpose of putting an individual through this mental torment expect for the fact that they could better prepare themselves for the conditions onset and eventual death.

Personal Opinion

I have mixed feelings from researching the topic of genetic screening. As with any new technology, exciting ideas and possibilities preoccupy our thinking. In our eagerness to grasp new genetic possibilities, we must not forget the unanswered questions that can leave us wondering how great this new knowledge really is. On the larger scale I would say that I am in favor of genetic testing...with a few qualifications.

The idea that we could identify genetic disorders in babies before they are even born is very exciting. Could there come a day when all diseases could be treated before the child is ever born into our hostile world? With this advancement comes the realization that we are playing God in determining who will be born healthy or not. It is unimaginable to me the emotions that a mother must endure once she discovers that her child will be born 'less than perfect'.

The other struggle that I face is with the power of genetic information in the workplace. I look forward to the opportunity to make work sites safer by ensuring that susceptible workers are identified and given the right to make informed decisions. Where does the line get drawn to determine when an individuals free choice is taken away and they are discriminated against because of genetic test results. Genetic information must be handled differently than other private information because it reveals knowledge not only about the individual but also about their family and ethnic group. This could lead into a trend of labeling a sex or ethnic group as inferior.

The future possibilities of genetic testing are very exciting. The challenge that I foresee is that we use this information to improve our livelihood and not as a means to set one group apart from another.


Blatt, Robin JR. 1996. An Overview of Genetic Screening and Diagnostic Tests in Health Care. Obtained from the WWW:

Eng, C., and J. Vijg. 1997. Genetic Testing: The Problems and the Promise. Nature Biotechnology 15:422-426.

McCarrick, Pat M. 1997. Genetic Testing and Genetic Screening. Obtained from the WWW:

Read My Genes: Genetic Screening in the Workplace. Obtained from the WWW:

Warmuth, Marc A., Linda Sutton, and Eric Winer. 1997. A Review of Hereditary Breast Cancer: From Screening to Risk Factor Modification. The American Journal of Medicine 102:407-415.

Student Essay List

Course Homepage