Privacy

Many similar concerns arise in the context of criminal law, including the potential uses of DNA databases. There are issues relating to the collection and maintenance of DNA samples or information from everyone who is arrested, whether or not they are convicted. There are issues relating to the collection and maintenance of DNA samples and/or information collected from individuals upon arrest. For example, the DNA and/or information obtained from certain individuals may be saved, even if the person is not convicted. Indeed, prosecutors have issued many arrest warrants in old cases based solely on stored DNA data. These warrants have resulted in successful prosecutions, but the question being asked in the courts is whether it is legal to base arrests solely on "cold hit identification" using DNA evidence.

In contrast to medically oriented genetic tests, the DNA tests used in criminal law generally do not test for the presence or absence of a particular gene, since the noncoding regions of a person's DNA can be distinguished much more easily from the DNA of other individuals. Different individuals have different DNA sequences in these noncoding regions because there is no evolutionary penalty for mutations in such regions, as they are not used to produce proteins.

This helps provide the high level of discrimination required in criminal cases, enabling a jury to say that, based in part on the DNA evidence, an accused person is guilty beyond a reasonable doubt. An important caveat however, and one not always understood by prosecutors or juries, concerns what a DNA match actually proves. While nonmatching DNA proves innocence, matching DNA does not prove guilt. In any large city, there will be at least a handful of people with similar DNA profiles. Even if DNA is found to be matching, a conviction must rely on other evidence, such as other physical evidence or eyewitness testimony.

Although the use of DNA data can assist investigations, there is an element of "big brother is watching" in its use. There are also concerns that by instituting wide programs of DNA collection based on arrests, not necessarily convictions, the practice will expand to other areas. For example, providing a DNA sample could be required, at some point, for obtaining a driver's license, marriage license, or social security number. There is also a question of what entities, including police departments, governmental agencies, employers, financial institutions, credit reporting businesses, and insurance carriers, would have access to the data. There is concern that by having genetic information recorded in a criminal record database, citizens would be subject to a wide variety of discrimination.