<https://www.nature.com/articles/d41586-019-03687-x> Across the world, DNA databases that could be used for state-level surveillance are steadily growing. The most striking case is in China. Here police are using a national DNA database along with other kinds of surveillance data, such as from video cameras and facial scanners, to monitor the minority Muslim Uyghur population in the western province of Xinjiang. Concerns about the potential downsides of governments being able to interrogate people’s DNA have been voiced since the early 2000s1 by activist groups, such as the non-profit organization GeneWatch UK, and some geneticists (myself included). Partly thanks to such debate, legislation and best practices have emerged in many countries around the use of DNA profiling in law enforcement2. (In profiling, several regions across the genome, each consisting of tens of nucleotides, are sequenced to identify a person or their relatives.) Now the stakes are higher for two reasons. First, as technology gets cheaper, many countries might want to build massive DNA databases. Second, DNA-profiling technology can be used in conjunction with other tools for biometric identification — and alongside the analysis of many other types of personal data, including an individual’s posting behaviour on social networks. Last year, the Chinese firm Forensic Genomics International (FGI) announced that it was storing the DNA profiles of more than 100,000 people from across China (FGI, known as Shenzhen Huada Forensic Technology in China, is a subsidiary of the BGI, the world’s largest genome-research organization). It made the information available to the individuals through WeChat, China’s equivalent of WhatsApp, using an app accessed by facial recognition. A pregnant woman and other migrants are apprehended by a Border Patrol agent With stringent safeguards and oversight, it is legitimate for law-enforcement agencies to use DNA-profiling technology. But these uses can easily creep towards human-rights abuses. In October this year, the US Department of Homeland Security announced that it would authorize the mandatory collection of DNA samples from immigrants in federal custody at the US border, including children and those applying for asylum at legal ports of entry. The resulting DNA profiles will be available through a database called CODIS (Combined DNA Index System), which includes the profiles of convicted offenders and individuals arrested for serious offences. Such treatment could reinforce debunked claims that immigrants are more prone to criminal behaviour than the general population. A much broader array of stakeholders must engage with the problems that DNA databases present. In particular, governments, policymakers and legislators should tighten regulation and reduce the likelihood of corporations aiding potential human-rights abuses by selling DNA-profiling technology to bad actors — knowingly or negligently. Researchers working on biometric identification technologies should consider more deeply how their inventions could be used. And editors, reviewers and publishers must do more to ensure that published research on biometric identification has been done in an ethical way. [...]