Science & technology | Small people; big data Should every baby’s DNA be sequenced? The genomic generation is on its way July 2nd 2026 Shortly after Freddie was born in April 2025, he was diagnosed with retinoblastoma, a rare form of eye cancer. It was spotted early and treated promptly, which means he has a much better chance of growing up with normal vision. That quick diagnosis was no accident. Freddie is part of the Generation Study, an English programme which plans to sequence the complete genetic code of 100,000 babies. The idea is both to screen them for genetic diseases and to use the collected genomic data to boost medical research in future. Similar trials are under way in America, Australia and parts of Europe, to test whether such screening should be offered for all newborns. Supporters hope to transform the diagnosis and treatment of rare diseases. Critics fret
that genomic sequencing may cause needless worry, and require parents to hand over sensitive data about their children. Many countries screen infants for diseases already, usually by taking a blood sample and looking for markers of conditions such as sickle-cell anaemia or cystic fibrosis. The most comprehensive screens, such as Italy’s, look for markers of around 50 diseases. Analysing DNA rather than blood can increase that number dramatically, as well as flagging mutations that are not causing problems yet, but might in future. The Generation Study is screening for around 200 conditions that arise in childhood. In America the BabySeq2 project screened for around 1,000 genes, some linked to diseases that emerge in adulthood such as breast or ovarian cancer. Catching more diseases earlier could help many more babies like Freddie. But there are worries to go with the enthusiasm. One is that genes are not always destiny. The average person carries scores of genetic variants that have been linked to diseases. But because of environmental factors, the influence of other genes or chance, most of those conditions never develop. Geneticists use a concept called “penetrance” to describe the proportion of people with a disease-causing mutation who actually go on to become ill. It can vary greatly for different conditions—and many estimates may be too high. Many disease-causing mutations are found by working backwards from people who are already ill, which risks inflating the numbers. Take retinoblastoma. Early studies estimated that mutations in a gene called RB1 had penetrance of more than 90%. But a paper posted online in December found that less than a third of adults with risky variants have ever had the cancer. “I think historically people have equated genetic information with certainty,” says Caroline Wright a geneticist at the University of Exeter, who conducted the study, “which is quite outdated now.” Testing hundreds of genes with low or middling penetrance could create “patients-in-waiting” many of whom will never become ill. Such diagnostic purgatory is stressful enough that, in the case of cystic fibrosis, it has a name: “cystic fibrosis, screen positive inconclusive diagnosis” (CFSPID). Parents of CFSPID children often question the worth of getting the test results at all, says Anneke Lucassen, a geneticist at the University of Oxford.
Uncertainty is not the only worry. Some treatments can cause harm too. In the case of retinoblastoma a risky mutation triggers only eye tests. But for medullary thyroid cancer caused by mutations in the RET gene (where new research also suggests penetrance is much lower than had been thought), a common follow-up is to surgically remove the thyroid gland. That leaves patients dependent on artificial thyroid hormones for the rest of their lives. Some of the issues have solutions. Results could be given for only genetic variants which give rise to treatable illnesses, and which are known to have high penetrance—though that might upset those who would prefer to know everything. Careful communication can improve understanding of a test’s limitations. Part of the point of the trials is to explore exactly these sorts of questions. But screening is only half the story. A second goal of most programmes is to store the genomes for use in future research. Such databases can be very useful. Data from Britain’s 100,000 Genomes Project, which collected genomes from patients with rare diseases and their families, allowed researchers at Oxford to spot genetic variants that cause a neurodevelopmental disorder in children. The data could also be used to predict drug side-effects and predict how well a patient will respond to treatment. It could also be used to flag people who might benefit from new treatments that did not exist when their genomes were first stored. “I’m completely confident that our ability to understand the genome will improve,” says Ewan Birney, director of the European Bioinformatics Institute. “AI is giving us a massive boost to that.” On the other hand, a person’s genome is among the most personal and sensitive information there is. For some researchers and parents, the idea of storing it indefinitely is a sticking-point. There have been several leaks of genetic or medical information in recent years. In 2023, for instance, hackers stole the genetic and personal information of 6.9m customers of 23andMe, a beleaguered direct-to-consumer genetic-testing company. The same advances in genetics that enable new treatments are also likely to enable new uses for genetic information outside medicine. In America some insurers can already use genetic-test results when setting premiums (in
Australia and Britain this is mostly banned). Insights from DNA could be used for blackmail, for instance around questions of paternity. Jan Friedman, a geneticist at the University of British Columbia, worries that many of the proposed screening programmes suffer from “mission creep”, with most requiring parents to sign up to both screening and the long-term storage of their child’s data for research. “You can’t take part in one without taking part in the other,” says Dr Lucassen of the University of Oxford, yet “they’re so different”. Screening programmes are usually judged on whether the benefits to the patients outweigh the costs. Medical research, by contrast, is justified by benefits that are uncertain and often accrue to other people. Current genomic-screening trials for newborns are trying to do both at once, and with patients who are incapable of consenting to boot. The benefits could be enormous. But the ethics look tricky. ■ Correction: an earlier version of this article said Freddie had been treated with photo-activated chemotherapy. This has been amended. Curious about the world? To enjoy our mind-expanding science coverage, sign up to Simply Science, our weekly subscriber-only newsletter. This article was downloaded by zlibrary from https://www.economist.com//science-and-technology/2026/06/29/should-every-babys- dna-be-sequenced
Science & technology | Digging deeper Scientists can now study the event horizons of black holes They make the universe’s most extreme gravitational laboratories July 2nd 2026 A LONG TIME ago, in a galaxy far, far away—somewhere in the general direction of the constellation of Leo—two black holes crashed together and merged. About 1.3bn years later, on January 14th 2025, a blip appeared in the detectors at the Laser Interferometer Gravitational-Wave Observatory (LIGO), an instrument based in Louisiana and Washington state. The blip marked the arrival of the pulse of gravitational waves—ripples in the fabric of the universe—emitted as the black holes collided. In a paper published in Nature on June 24th, a team led by Sizheng Ma of Perimeter Institute for Theoretical Physics, in Ontario, report that they have used those
waves to glimpse one of nature’s strangest phenomena: the “event horizons” that surround black holes. An event horizon marks the point beyond which gravity so warps spacetime that nothing, not even light, can escape. An object that crosses the horizon is cut off from the rest of the universe, with all possible roads leading to the black hole’s centre. Event horizons are invisible, although their effects can often be seen when a black hole is swallowing hot, glowing gas. Physicists nevertheless know a great deal about how they work, thanks to Albert Einstein’s theory of general relativity. But physics is an empirical science as well as a theoretical one. Dr Ma thought that gravitational waves might offer a way to check that Einstein’s theory does indeed match reality at the boundary of a black hole. General relativity predicts that as two black holes collide and merge, the properties of the new hole’s event horizon should be imprinted on the gravitational waves released. To test this, Dr Ma teamed up with physicists from LIGO, who are used to interpreting the complex signals that show up in their detectors. Since the wave detected last year is the clearest from a binary merger so far detected, the team focused their attention there. Sure enough, they were able to decipher the part of the signal in question. And it matched their theoretical prediction exactly. The team’s new technique provides an unprecedented view of the bizarre environment just outside an event horizon. Here light loses energy as it attempts to climb out of the black hole’s immense gravitational field. That makes objects approaching the horizon appear redder and redder to outside observers. As the black hole rotates it tugs the fabric of spacetime around with it, warping distances and the passage of time. The physics of both of these effects are captured in the rumble of the gravitational waves, allowing physicists to probe gravity at its most extreme. Or nearly its most extreme. Hidden behind the event horizon, at the heart of the black hole, is an even stranger region: the singularity. There the gravitational field is so intense that Einstein’s theory starts to give nonsensical results. Most physicists see that as a hint that some new, more fundamental theory remains to be discovered—probably one that combines
gravity with quantum mechanics, a feat that has eluded physicists for decades. Event horizons are as close as the universe allows physicists to get to singularities. That makes them “very interesting from the point of view of understanding the incompatibility between quantum mechanics and general relativity”, says Nicolas Yunes, a physicist at the University of Illinois Urbana-Champaign, who was not involved in the new study. He hopes that “whispers of quantum-gravitational effects” may linger near the event horizon. Now it may be possible to check. ■ Curious about the world? To enjoy our mind-expanding science coverage, sign up to Simply Science, our weekly subscriber-only newsletter. This article was downloaded by zlibrary from https://www.economist.com//science-and-technology/2026/07/01/scientists-can-now- study-the-event-horizons-of-black-holes