Can some one give me 3 cons of genetic testing?

Genetic testing has limitations and possible drawbacks, including:

It's not yet clear exactly what you should or shouldn't do once you get your genetic test results. We still don't know the most effective ways to prevent breast cancer, although taking tamoxifen could lower your risk of developing the disease.
Removing the breasts and ovaries to lower cancer risk (called prophylactic surgery) does not get rid of every breast- and ovary-related cell. So even though it can lower your risk a lot, it still does not entirely eliminate the risk. Even after such surgery, a woman with an abnormal breast cancer gene must be monitored regularly. These diseases may show up in nearby tissues and organs.
Normal test results don't guarantee healthy genes. In some families, many women have had breast cancer, yet they all test normal for the known breast cancer mutations. These families may have an inherited form of breast cancer caused by an abnormality or other gene that simply hasn't been identified yet. A woman from such a family must be followed closely.
For more information on genetic testing, counseling, and support, visit the FORCE (Facing Our Risk of Cancer Empowered) web site.

Close monitoring does not always succeed in detecting breast cancer early. Some women end up being diagnosed with later-stage disease despite the best surveillance techniques.
For some women, an abnormal test result can trigger anxiety, depression, or anger. Even though the result doesn't mean that a woman will definitely get breast cancer, many women with an abnormal gene assume they will. If you think knowing the information may be too hard for you emotionally, consider not having genetic testing until more is known about how to beat the disease.
If you learn that you've passed on an abnormal gene to your children, you may feel guilty and worried. (Yet such knowledge may also prepare you for helping your children cope with their genetic information.)
You could face discrimination鈥攊n getting insurance coverage or employment鈥攂ased on your genetic information. Advances in breast cancer genetic testing have out paced legal protections for those identified through such testing. Although basic legislation exists in the United States to protect most people from such discrimination, privacy remains a serious issue. Carelessness and leaks could reveal your test results to others. So far, however, no cases of discrimination related to genetic information are known to have occurred.
Genetic testing may not answer all your questions. In families with an abnormal breast cancer gene, other factors that are not yet understood may contribute to high risk.

Clinical genetic tests are not just descriptive as many laboratory tests are (such as describing the glucose level in your blood), but they are predictive as well. Predictive tests will not give a yes/no answer, but instead will tell what the chances are of developing a particular genetic condition. Such results are not definitive and may leave a person wondering what to do with those results, particularly if available treatments or therapies limit the course of action.


A particular genetic test will only tell if there is specific genetic variant, or mutation; it cannot guarantee whether the disease will develop nor can the test provide information about other genetic diseases not being specifically looked for by that test.


While the test may detect a particular problem gene, it cannot predict how severely the person carrying that gene will be affected. Again with cystic fibrosis, symptoms may be mild bronchial abnormalities or they may range to severe lung, pancreatic, and intestinal problems.

You might find out something you don't want to know.

Genetics alone don't tell the whole story. You may have some genetic pre-dispositions, but they probably won't manifest themselves unless other conditions are present (e.g. environmental preassures)

We aren't completely positive about some genetic markers.

Getting "labled" as having a genetic pre-disposition toward a disease could be used against you by insurance companies or in other forms of discrimination.

It's best not to mess with genetic testing unless you know exactly what you're looking for.

First off, segregation against certain DNA types. Say, in the work force, if it's known you're going to have a certain kind of debilitating cancer, an employer could higher someone without that gene so that they wouldn't lose a worker. Or, healthcare providers screen genes before giving coverage.

Second, it's not just the genes that make the person, it's how they interact with the environment. Someone prone to cancer or a disease can possibly put it off or keep it away because of their way they carry out their life. Or, someone who is genetically healthy could get debilitating diseases because they didn't care for their body.

Third, it opens the air for new drugs, and since our understanding of genetics still isn't that great, they could have lasting and dire consequences when they were made to combat something specific.

The one con I don't see in the many good ones listed is: erroneous results.
With many of the genetic marker tests, the test is not necessarily for the exact gene that causes the problem but for a gene that is nearby and is USUALLY associated with or sorted into daughter cells along with the defective gene.
Another source of error is "Chimerism" or "Mosaicism" where a single individual has cells with two different genetic make-up. Some tissues may be at risk for the disease and others are not.
This ignores technical error, and clerical error and subterfuge.