What is genetic testing?

A genetic test examines the DNA (deoxyribonucleic acid) of a person's cells. Genetic testing can identify abnormal genes, or analyze the number, arrangement and characteristics of the chromosomes. Testing may be performed on samples of blood, semen, urine, saliva, stool, body tissues, bone or hair.

You inherit half of your genetic information from your mother and the other half from your father. Genes, alone or in combination, determine what features (genetic traits) a person inherits from his or her parents, such as blood type, hair color, eye color and other characteristics, including risks of developing certain diseases. Certain changes in genes or chromosomes may cause medical problems.