Is it fair for police to search DNA databases for a suspect's relatives?

People disagree, and the answer depends on whom you ask. Familial DNA searching is the practice of creating new leads when a crime-scene DNA profile strongly resembles, but does not exactly match, a profile in a database. Software compares the crime-scene profile with every stored profile and lists the offenders most likely to be a very close relative of the person whose DNA was found. Close relatives share a higher percentage of alleles than random members of society, so a near-match can point to a family.

It has solved cases. Familial searching was first used in an investigation leading to a conviction in the case of Jeffrey Gafoor, convicted in 2003 of the 1988 murder of Lynette White. DNA evidence was matched to Gafoor's nephew, who at 14 years old had not been born at the time of the murder. In 2010 it was used in the case of the Los Angeles serial killer known as the Grim Sleeper, who had eluded police for more than two decades. The tip-off came from the DNA of the suspect's own son, who had been swabbed the year before after a felony weapons conviction.

Critics say the technique invades individuals' Fourth Amendment rights, because someone is implicated only because a relative's DNA is in a database. They add that racial profiling could occur. Some scholars reply that the concerns are similar in some respects to those about other police search techniques, and most have concluded the practice is constitutional. As of 2011 it was not conducted at a national level in the United States, where states decide how and when to use it. Such a question has no single answer, and societies are still choosing.