DNA testing methods vary, but most methods can perform with very high levels of accuracy.
There are many reasons why you might want to get a DNA test. Although we often see DNA testing used in TV forensics shows, and in fact DNA testing is used in real life criminal cases, the most common reason out there for getting a DNA test is to determine paternity. DNA paternity testing conclusively determines if a man is the father of a particular child. DNA maternity tests and sibling tests are also available. For those who are interested in genealogy or ethnic origins, many DNA labs now offer DNA ancestry testing.