When You Are Not the Father, But You Are the Suspect

Last Modified: January 13, 2023
January 10, 2023 | Rabin Nabizadeh | General Topics

Using genealogical research in solving crimes has become the new go-to for law enforcement agencies worldwide. When a suspect in a decades-old murder case is finally apprehended and brought to trial, the entire community, often the entire world, breathes a sigh of relief. Justice has finally been served.

But how just is a criminal prosecution that hinges on an arguably unconstitutional investigation tactic? One that necessarily includes delving into the most intimate, private information of not only the suspect but of his or her family members as well? 

DNA and DNA Testing

DNA, or deoxyribonucleic acid, is a sequence of genetic information containing nucleotides, the biological building blocks of every living organism. DNA strands contain the instructions that are necessary for an organism to grow and reproduce.

DNA strands are, quite literally, the unique blueprints of all living matter. In 1985, DNA testing was in its infancy, but in the intervening 35 years, DNA testing of biological material (skin cells, hair follicles, blood and bodily fluids) has emerged as the most “reliable” type of physical evidence collected at any crime scene.

DNA testing can uncover distinctive patterns in genetic materials and can narrow a field of suspects down to one individual, often with more than 99% accuracy. DNA evidence testing has led to the arrests and convictions of thousands of people.

Since its inception as an accepted investigative tool, all 50 states and the federal government have passed laws requiring that DNA samples be collected from people convicted of certain offences and uploaded to the Combined DNA Index System (CODIS).

Law enforcement agencies routinely use CODIS as an investigative tool when searching for an unknown subject. DNA evidence has been credited with the arrests and convictions of Green River Killer Gary Ridgway, Golden State Killer Joseph James DeAngelo, and Grim Sleeper Lonnie Franklin, Jr.

But when does chasing DNA evidence through a federally-maintained database pivot to plumbing the depths of private databases marketed to the general public as ancestral research tools?

Bachelor Number One

In 2018, law enforcement officers arrested Joseph James DeAngelo based on decades-old DNA evidence. DeAngelo was subsequently charged with 13 counts of murder and 13 counts of kidnapping related to a string of violent crimes that took place across the state of California beginning in 1974.

DeAngelo pled guilty in 2020 and was sentenced to life in prison. The resolution of “cold” cases such as DeAngelo’s almost always foments media firestorms, but DeAngelo’s case sparked an incendiary debate across the country.

In desperation to find the alleged culprit, law enforcement agencies investigating the Golden State Killer’s crimes turned to a DNA testing company when their searches of CODIS and similar databases were unsuccessful.

Advances in genetic testing have streamlined the process, making it quicker and less expensive. This gives rise to companies like Ancestry.com and 23andMe, which offer genetic testing to the general public to uncover racial backgrounds and long-lost family members.

Companies like 23andMe store customers’ genetic material and aggregated DNA profiles and then sell or share this information with pharmaceutical companies for “disease research.”

In fact, pharmaceutical giant GlaxoSmithKline was the first pharmaceutical company to enter into a commercial contract with 23andMe, spending nearly $300 million in 2018 on the deal.

In return for the investment, GlaxoSmithKline’s biomedical researchers were granted unfettered access to genetic data from 23andMe customers.

More alarmingly, most private DNA companies allow or actively encourage law enforcement agencies to use their voluminous databases to assist in criminal investigations. While customers can opt out of providing this type of access, surprisingly, most do not. Once that information is made public, all privacy bets are off.


In late 2010, a public database called GEDmatch launched its genetic genealogy research services. GEDmatch is a veritable clearinghouse of autosomal DNA test data that collects DNA sequences from consumers who use private companies like 23andMe and AncestryDNA.

The difference is that GEDmatch is a public database. Law enforcement agencies can upload a suspect’s DNA sequence to GEDmatch, which can be searched to find similar profiles among more than one million users.

Those genetic profiles are collected from 23andMe or AncestryDNA from consumers who voluntarily took a DNA test. GEDmatch spits out a list of potential familial relations based on the DNA sequence that has been uploaded. And GEDmatch, as a public service, has far fewer restrictions on sharing personal data.

Law enforcement officials use this service to find people in the database whose DNA sequences are closely related to the DNA sequence collected from a particular crime scene.

The Unethical Use of DNA Testing Results

A person shares 50% of his or her DNA with a parent, 25% with a grandparent, 12.5% with a first cousin, and approximately 3% with a second cousin. GEDmatch searches can be tailored to how close or distant a match the investigator wants to uncover. 

The use of genetic genealogy research via private testing companies has raised significant concerns of unconstitutionality about the privacy of direct-to-consumer DNA testing.

University of Baltimore Professor of Law Natalie Ram co-writes in a 2018 essay in Science magazine that “eroding limits on the use of crime-solving technology threatens our collective civil liberties and opens the door to socially and politically unacceptable genetic surveillance.”

The main issue is this: to use 23andMe or AncestryDNA as tools in criminal investigations, law enforcement agencies would normally need to provide a “clean” saliva sample from a potential suspect to the company for analysis.

Most crime scenes do not yield that type of genetic material, as the material is often contaminated by other substances. However, newer companies such as GEDmatch can collect, store and analyze raw DNA data from testing companies.

According to Ram, this means that “law enforcement investigators are equally able, if they have enough DNA to create a sufficiently complete genetic sequence, [and] upload that to GEDmatch” to search for potential suspects.

Even though companies like 23andMe and AncestryDNA require explicit consent from the person whose DNA is to be tested, GEDmatch does not. In fact, GEDmarch deliberately changed its terms of service to allow law enforcement access to its extensive databases. 

The Price is Right

The Constitution of the United States protects citizens’ rights to due process and privacy. The first major Supreme Court case to recognize the “right to privacy” was the 1965 decision in Griswold v. Connecticut, 381 U.S. 479 (1965).

The Griswold court used the personal protections expressly stated in the First, Third, Fourth, Fifth, and Ninth Amendments as the foundation of a finding of an implied right to privacy. Later Supreme Court decisions explicitly tied this fundamental right to medical records and information.

Within the last decade, several states have begun allowing the use of private DNA databases for “familial DNA searches.” These searches input DNA samples and find people whose DNA matches those samples.

Once those “familial” matches are found, law enforcement officers look for all relatives of those people to see if any of their genetic materials match the DNA sample left at a crime scene. These familial matches have been used to arrest and convict people of crimes from murder and rape to a residential burglary.  

How Does the Unethical Use of DNA Testing Results Affect Your Family

Given that Americans are still entitled to the protections afforded by the Constitution, do these genetic genealogy searches go too far? Arguably, genetic data extracted from DNA should be treated differently than other medical information, given the extremely personal nature of the information.

Where medical records reveal information about a particular person who is the subject of the records, DNA data also reveal information about that person’s relatives, who were never allowed to consent to access their personal information in the first place.

Where private companies like 23andMe and AncestryDNA are beholden to stricter medical privacy laws for their customers, GEDmatch is a public database where those privacy protections do not apply.

Once consumers voluntarily relinquish their genetic data to these companies, it ceases to belong solely to them. It is tantamount to cutting your fingernails and throwing the clippings away. Law enforcement can come and collect them without a warrant.

Although there is a well-established canon of law in the United States protecting citizens against warrantless searches, genetic genealogy research and DNA data as investigative tools is such a new phenomenon that the governance of their use does not fall squarely within the purview of established case law.

The Risk of Genetic Data Mining in Criminal Investigations

So what is the risk of permitting the use of genetic data mining in the pursuit of justice?

Shouldn’t we all want people who commit violent crimes to be apprehended and brought to trial? And, if the suspect’s arrested through genetic genealogy research are ultimately found guilty by a court of law, how much do we really care about how they were apprehended?

The answer is multilayered but startlingly simple: potential due process and other Constitutional violations aside, the root issue is the commodification of genetic data. The literal auctioning off of our most intimate medical information to the highest bidder.

When we allow private and public companies to buy and sell information as personal as the specific roadmap replicating each and every one of us, we risk losing the one thing we have not yet voluntarily relinquished: who we are as unique human beings. Once we cede that, we cease to exist as individuals.

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