If you were born in the United States within the last 50 or so years, chances are good that one of the first things you did as a baby was give a DNA sample to the government. By the 1970s, states had established newborn screening programs, in which a nurse takes a few drops of blood from a pinprick on a baby’s heel, then sends the sample to a lab to test for certain diseases. Over the years, the list has grown from just a few conditions to dozens. The blood is supposed to be used for medical purposes—these screenings identify babies with serious health issues, and they have been highly successful at reducing death and disability among children. But a public records lawsuit filed last month in New Jersey suggests these samples are also being used by police in criminal investigations. The lawsuit, filed by the state’s Office of the Public Defender and the New Jersey Monitor, a nonprofit news outlet, alleges that state police sought a newborn’s blood sample from the New Jersey Department of Health to investigate the child's father in connection with a sexual assault from the 1990s. Crystal Grant, a technology fellow at the American Civil Liberties Union, says the case represents a “whole new leap forward” in the misuse of DNA by law enforcement. “It means that essentially every baby born in the US could be included in police surveillance,” she says. It’s not known how many agencies around the country have sought to use newborn screening samples to investigate crimes, or how often those attempts were successful. But there is at least one other instance of it happening. In December 2020, a local TV station reported that police in California had issued five search warrants to access such samples , and that at least one cold case there was solved with the help of newborn blood. “This increasing overreach into the health system by police to get genetic information is really concerning,” Grant says. Privacy activists have also raised alarms about what they see as similar misuses of other kinds of DNA collection. In a recent case, police in San Francisco used a sample collected during a woman’s rape exam to tie her to an unrelated property crime years later . Chesa Boudin, who was then the city’s district attorney, called this use of the woman's DNA a violation of her Fourth Amendment right against unreasonable searches and seizures, and ultimately dropped the charges. The New Jersey lawsuit alleges that police obtained the blood sample of a newborn child (who is now elementary-school aged) to perform a DNA analysis that linked the baby's father to a crime. This was done using a technique called investigative genetic genealogy, or forensic genealogy. It usually involves isolating DNA left at a crime scene and using it to create a digital genetic profile of a suspect. Investigators can upload this profile to genealogy websites where other people have freely shared their own DNA information in the hope of connecting with family members or learning about their ancestry . Because DNA is shared within families, investigators can use relative matches to map out a suspect’s family tree and narrow down their identity. According to the New Jersey lawsuit, police had reopened an investigation into a cold case and had used genetics to place the suspect within a single family: one of several adults or their children. But police didn’t yet have probable cause to obtain search warrants for DNA swabs from any of them. Instead, they asked the state’s newborn screening lab for a blood sample of one of the children. Analysis of this genetic information revealed a close relationship between the baby’s DNA and the DNA taken at the crime scene, indicating that the baby’s father was the person police were seeking. That was enough to establish probable cause in the assault investigation, so police sought a warrant for a cheek swab from the father. After analyzing his DNA, the suit contends, police found that it was a match to the crime scene DNA. Jennifer Sellitti, an attorney with the Office of the New Jersey Public Defender, which is representing the father, says combining newborn screening samples with genetic genealogy opens the door for virtually anyone’s DNA to be used in a criminal investigation. “This is like a dystopian onion. Every time we peel back another layer, we find some new violation of privacy,” she says. The lawsuit targets the New Jersey Department of Health and the state-run lab that conducts newborn screening. In an email to WIRED, Nancy Kearney, a spokesperson for the department, said they do not comment on pending litigation. She did not respond to a request to comment more generally on the department’s policies regarding retention or use of newborn screening samples. When contacted by WIRED, a spokesperson for the New Jersey State Police also said that the agency does not comment on pending litigation. A representative from the New Jersey Office of the Attorney General, which is representing the state in the records lawsuit, said the office had no comment. Genetic genealogy was most famously used to identify Joseph James DeAngelo as the Golden State Killer in 2018. It’s since been used by US law enforcement agencies to solve hundreds of violent crime cases, many of which had gone cold for years. The technique is powerful because it gives police access to DNA databases outside of their traditional purview . Until recently, the main database at law enforcement’s disposal was the Combined DNA Index System, or Codis, which is maintained by the FBI. Codis contains around 14 million DNA profiles, but there are strict rules for what kind can be submitted: those of people arrested for or convicted of felonies, and unidentified remains. But anyone can take a consumer DNA test and upload their genetic profile to genealogy websites, some of which allow police access. It was only a matter of time before police turned to newborn blood samples, says Natalie Ram, a law professor at the University of Maryland. “In this post-Golden State Killer world, law enforcement is now looking around and seeking to identify suspects using genetic samples or genetic data outside of the official law enforcement repositories,” she says. In a recent article in the Texas Law Review, Ram analyzed state policies regarding newborn screening programs. She found that while many would theoretically protect these blood samples from police use, other state statutes, such as New Jersey’s, are unclear. Because there are no federal laws governing newborn screening programs, states set their own policies on which diseases they test for, how long samples are stored, and how they can be used. Some states hold on to blood samples for months, others for years or decades. Virginia only keeps samples from infants with normal results for six months, while Michigan retains them for up to 100 years. New Jersey stores samples for 23 years before destroying them. “There are so many ways that genetic material can be misused, and storing it for 23 years is just a recipe for that misuse to happen,” Sellitti says. These screenings are mandatory in the US. (Parents don’t have to provide consent, although they may opt out on religious grounds. ) Newborn blood samples can also be used for biomedical research, and only a handful of states require parental consent for those research purposes. Sellitti says parents deserve to know how their children’s DNA is being stored and shared, and for how long. To learn how often New Jersey police try to obtain this genetic data, the Office of the Public Defender and the New Jersey Monitor initially filed a records request with the state asking how many times police had asked for newborn screening samples and which law enforcement agencies made the requests. When the state declined to answer, Sellitti says, the office filed a suit to force the state to disclose how widespread the practice is in New Jersey. Sellitti says she hopes the suit will spur the state to reconsider how newborn genetic samples should be used. “We think there are changes that can be made to the way this information is being stored, and that parents should have very clear access to that information,” she says. .