Genetic testing involves examining a person's DNA in order to find changes or mutations that might put an individual, or that individual's children, at risk for a genetic disorder. These changes might be at the chromosomal level, involving extra, missing, or rearranged chromosome material. Or the changes might be extremely small, affecting just one or more of the chemical bases that make up the DNA. In a broader sense, genetic testing includes other types of testing that provide information about a person's genetic makeup, such as enzyme testing to diagnose or identify carriers for a genetic condition such as Tay-Sachs disease.

With hundreds of genetic tests available, determining who should be offered testing and under what circumstances testing should occur is relatively complicated. In general, testing is offered to those at highest risk based on their ethnic background, family history, or symptoms. However, just because genetic...