Last week, Maryland and Montana passed laws requiring judicial authorization to search consumer DNA databases in criminal investigations. These are welcome and important restrictions on forensic genetic genealogy searching (FGGS)—a law enforcement technique that has become increasingly common and impacts the genetic privacy of millions of Americans.

Consumer personal genetics companies like Ancestry, 23andMe, GEDMatch, and FamilyTreeDNA host the DNA data of millions of Americans. The data users share with consumer DNA databases is extensive and revealing. The genetic profiles stored in those databases are made up of more than half a million single nucleotide polymorphisms (“SNPs”) that span the entirety of the human genome. These profiles not only can reveal family members and distant ancestors, they can divulge a person’s propensity for various diseases like breast cancer or Alzheimer’s and can even predict addiction and drug response. Some researchers have even claimed that human behaviors such as aggression, or ideological beliefs such as politics, can be explained, at least in part, by genetics. And private companies have claimed they can use our DNA for everything from identifying our eye, hair, and skin colors and the shapes of our faces; to determining whether we are lactose intolerant, prefer sweet or salty foods, and can sleep deeply. Companies will even create images of what they think a person looks like based just on their genetic data. Claims like these, which are often presented as fact, are dangerous because they can be seized on by law enforcement to target marginalized communities and can lead to people being misidentified for crimes they didn't commit.

Through FGGS, Law enforcement regularly accesses this intensely private and sensitive data. Just like consumers, officers take advantage of the genetics companies’ powerful algorithms to try to identify familial relationships between an unknown forensic sample and existing site users. These familial relationships can then lead law enforcement to possible suspects. However, in using FGGS, officers are rifling through the genetic data of millions of Americans who are not suspects in the investigation and have no connection to the crime whatsoever. This is not how criminal investigations are supposed to work. As we have argued before, the language of the Fourth Amendment, which requires probable cause for every search and particularity for every warrant, precludes dragnet warrantless searches like these. A technique’s usefulness for law enforcement does not outweigh people’s privacy interests in their genetic data.

Up until now, nothing has prevented law enforcement from rifling through the genetic data of millions of unsuspecting and innocent Americans. The new laws in Maryland and Montana should change that.

Here’s What the New Laws Require:


Maryland’s law is very broad and covers much more than FGGS. It requires judicial authorization for FGGS and places strict limits on when and under what conditions law enforcement officers may conduct FGGS. For example, FGGS may only be used in cases of rape, murder, felony sexual offenses, and criminal acts that present “a substantial and ongoing threat to public safety or national security.” Before officers can pursue FGGS, they must certify to the court that they have already tried searching existing, state-run criminal DNA databases like CODIS, that they have pursued other reasonable investigative leads, and that those searches have failed to identify anyone. And FGGS may only be used with consumer databases that have provided explicit notice to users about law enforcement searches and sought consent from those users. These meaningful restrictions ensure that FGGS does not become the default first search conducted by law enforcement and limits its use to crimes that society has already determined are the most serious.

The Maryland law regulates other important aspects of genetic investigations as well. For example, it places strict limits on and requires judicial oversight for the covert collection of DNA samples from both potential suspects and their genetic relatives, something we have challenged several times in the courts. This is a necessary protection because officers frequently and secretly collect and search DNA from free people in criminal investigations involving FGGS. We cannot avoid shedding carbon copies of our DNA, and we leave it behind on items in our trash, an envelope we lick to seal, or even the chairs we sit on, making it easy for law enforcement to collect our DNA without our knowledge. We have argued that the Fourth Amendment precludes covert collection, but until courts have a chance to address this issue, statutory protections are an important way to reinforce our constitutional rights.

The new Maryland law also mandates informed consent in writing before officers can collect DNA samples from third parties and precludes covert collection from someone who has refused to provide a sample. It requires destruction of DNA samples and data when an investigation ends. It also requires licensing for labs that conduct DNA sequencing used for FGGS and for individuals who perform genetic genealogy. It creates criminal penalties for violating the statute and a private right of action with liquidated damages so that people can enforce the law through the courts. It requires the governor’s office to report annually and publicly on law enforcement use of FGGS and covert collection. Finally, it states explicitly that criminal defendants may use the technique as well to support their defense (but places similar restrictions on use). All of these requirements will help to rein in the unregulated use of FGGS.


In contrast to Maryland’s 16-page comprehensive statute, Montana’s new law is only two pages and less clearly drafted. However, it still offers important protections for people identified through FGGS.

Montana’s statute requires a warrant before government entities can use familial DNA or partial match search techniques on either consumer DNA databases or the state’s criminal DNA identification index. 1 The statute defines a “familial DNA search” broadly as a search that uses “specialized software to detect and statistically rank a list of potential candidates in the DNA database who may be a close biological relative to the unknown individual contributing the evidence DNA profile.” This is exactly what consumer genetic genealogy sites like GEDmatch and FamilyTree DNA’s software does. The statute also applies to companies like Ancestry and 23andMe that do their own genotyping in-house, because it covers “lineage testing,” which it defines as “[SNP] genotyping to generate results related to a person's ancestry and genetic predisposition to health-related topics.”

The statute also requires a warrant for other kinds of searches of consumer DNA databases, like when law enforcement is looking for a direct user of the consumer DNA database. Unfortunately, though, the statute includes a carve-out to this warrant requirement if “the consumer whose information is sought previously waived the consumer’s right to privacy,” but does not explain how an individual consumer may waive their privacy rights. There is no carve out for familial searches.

By creating stronger protections for people who are identified through familial searches but who haven’t uploaded their own data, Montana’s statute recognizes an important point that we and others have been making for a few years—you cannot waive your privacy rights in your genetic information when someone else has control over whether your shared DNA ends up in a consumer database.

It is unfortunate, though, that this seems to come at the expense of existing users of consumer genetics services. Montana should have extended warrant protections to everyone whose DNA data ends up in a consumer DNA database. A bright line rule would have been better for privacy and perhaps easier for law enforcement to implement since it is unclear how law enforcement will determine whether someone waived their privacy rights in advance of a search. 

We Need More Legal Restrictions on FGGS

We need more states—and the federal government— to pass restrictions on genetic genealogy searches. Some companies, like Ancestry and 23andMe prevent direct access to their databases and have fought law enforcement demands for data. However, other companies like GEDmatch and FamilyTreeDNA have allowed and even encouraged law enforcement searches. Because of this, law enforcement officers are increasingly accessing these databases in criminal investigations across the country. By 2018, FGGS had already been used in at least 200 cases. Officers never sought a warrant or any legal process at all in any of those cases because there were no state or federal laws explicitly requiring them to do so. 

While EFF has argued FGG searches are dragnets and should never be allowed—even with a warrant, Montana and Maryland’s laws are still a step in the right direction, especially where, as in Maryland, an outright ban previously failed. Our genetic data is too sensitive and important to leave it up to the whims of private companies to protect it or to the unbridled discretion of law enforcement to search it.

  • 1.  The restriction on warrantless familial and partial match searching of government-run criminal DNA databases is particularly welcome. Most states do not explicitly limit these searches (Maryland is an exception and explicitly bans this practice), even though many, including a federal government working group, have questioned their efficacy.