Genetic testing is used to determine the risk of a patient or their offspring developing genetic diseases. This is done through DNA sequencing in adults and preimplantation genetic diagnosis (PDG) on embryos. These genetic testing methods are effective ways to determine the likelihood of developing diseases such as Huntington's disease, a disease resulting from a trinucleotide repeat on chromosome 4p16.3 that causes uncontrollable muscle movements and decreased cognitive function. However, they only determine probability, which is not a completely reliable way to know whether symptoms will appear or not. Patients have the right to opt for genetic testing of their own DNA, even if they accept great risk in doing so. DNA is unique to each individual, present in each individual from conception, and influences who each individual is, so the information it contains belongs to each patient, despite the risks. These risks include DNA testing services providing results to potential employers or insurers, who may make decisions to the disadvantage of patients if high probabilities of disease are discovered. The results may also cause patients to react poorly emotionally and make negative lifestyle changes. Although risky, patients deserve the right to take these risks if they choose to do so. Genetic testing involves testing the DNA in a patient's blood to detect genetic disorders. This can be used to predict the disease risk of an embryo, unborn infant, or adult patient, including the risk of passing a genetic disease to their offspring (National Institute of Health [NIH] , 2013). To test adult patients, a blood sample is first taken from the patient and the DNA ...... middle of article ...... on episode of the series]. In P. Apsell (executive producer), Nova. Arlington, VA: PBS Lyons, RH (2004). How to sequence DNA? In An Introduction to the Structure and Function of DNA. Retrieved from http://seqcore.brcf.med.umich.edu/doc/educ/dnapr/sequencing.html Mahdieh, N. and Rabbani B. (2013). An overview of methods for detecting mutations in genetic disorders. Iranian Journal of Pediatrics, 23(4), 375-388. PMCID: PMC3883366National Institute of Health. (2014). HTT huntingtin [Homo sapiens (human)]. Retrieved from the United States National Library of Medicine, Genetics Home References website: http://www.ncbi.nlm.nih.gov/gene/3064National Institute of Health. (2013). Genetic testing. Retrieved from US National Library of Medicine, Medline Plus website: http://www.nlm.nih.gov/medlineplus/genetictesting.htmlOnline Mendelian Inheritance in Man. (2014). HUNTINGTON’S DISEASE; HD. MIM number: 143100