To search or not to search, that is the question. And despite some vocal criticisms and concerns regarding the practice of familial DNA searching, increasingly the answer is “yes.” What that means for the forensic community in its entirety remains to be seen, but for states that have moved forward with familial searching programs, protocols continue to be refined.

Forensic familial DNA searching for investigative purposes has made headlines in recent years, particularly with the capture and prosecution of the high-profile “Grim Sleeper” serial killer suspect in California. In this case, a search of California’s DNA database revealed that the DNA from a young man who had recently been arrested in the Los Angeles area partially matched samples taken from Grim Sleeper crime scenes. The match strongly indicated that this man was either the child or parent of the person committing these crimes. From that lead, detectives narrowed the investigation to the arrestee’s father, tested a discarded slice of pizza the suspect left at public food court, and ultimately arrested Lonnie David Franklin Jr. as the Grim Sleeper.

Some experts suggest familial searching could increase the yield of investigative leads by up to 40%, helping law enforcement solve more crimes. The practice is used in the United Kingdom, California, and Colorado, was recently adopted in Virginia, and is under consideration in Pennsylvania. Florida has been informally using the practice for some years, and other states are considering adding the technique to their crime-solving arsenal.

While familial searching may be effective given a particular set of circumstances, many questions remain. Critics argue that the practice puts unsuspecting and law-abiding citizens under genetic surveillance and violates a constitutional right to privacy that shouldn’t be surrendered just because a relative has given up his rights by committing a crime. And, because the current U.S. databases have a disproportionate number of African American and Hispanic samples, others argue the practice is a new form of racial profiling.

One of the most prominent opponents of familial searching is Stephen Mercer, chief attorney for the Forensics Division of the Maryland Office of the Public Defender. Mercer was instrumental in helping Maryland categorically ban familial searches. Mercer also testified before the District of Columbia city council against familial searches, and the council amended its DNA collection statute to ban the practice. So far, D.C. and Maryland are the only states to take this approach. “In Maryland, we identified a trend toward continued expansion of the database that was disturbing,” said Mercer. “It heralded an era of unwanted genetic surveillance that just wasn’t reasonable. Why should I forfeit my rights just because a family member chooses to commit a crime? Is that reasonable? Genetic surveillance of a group that is largely defined by race is the harm in a democratic society.”

Mercer says the D.C. ban speaks volumes because rather than operating its own database as all 50 states do, D.C. samples are entered directly into the National DNA Index System (NDIS) database.