Genomics & Personalised Medicine
Your DNA Is a Story Someone Else Might Tell
The moment you spit into a tube for a ancestry kit, you've made a privacy decision not just for yourself, but for every biological relative you'll ever have.
The Idea
Most privacy frameworks are built around the individual — your data, your choice, your consent. Genomics breaks that model entirely. Your genome is approximately 50% identical to each of your parents and siblings, and shares meaningful overlap with cousins, half-siblings, and populations you may never have met. This means that when you share your genetic data — with a testing company, a researcher, or a hospital — you are, without their knowledge or agreement, sharing a partial map of theirs too. This is what ethicists call the 'non-individual nature of genetic information', and it creates a consent problem that nobody has cleanly solved. The standard bioethics toolkit — informed consent, the right to withdraw, data anonymisation — was designed for information that belongs to one person. Genomic data resists anonymisation in ways that other sensitive data does not. Researchers have demonstrated that individuals can be re-identified from supposedly anonymised genetic datasets by cross-referencing them with public genealogy databases. The more people who submit their DNA voluntarily, the easier this becomes for everyone. There is also a temporal dimension that makes this stranger still: genetic information is largely fixed at birth, so its implications can outlast any consent you give today. A teenager who joins a research study cannot fully anticipate what that data might reveal — or be used for — decades later, as our ability to interpret genomes continues to expand.
In the World
In 2018, investigators arrested Joseph James DeAngelo, the Golden State Killer, after more than forty years of evading detection. They did it not by obtaining his DNA directly, but by uploading crime scene DNA to GEDmatch, a publicly accessible genealogy database. From there, detectives built family trees from distant relatives who had voluntarily submitted their own DNA, eventually narrowing the pool to DeAngelo. The technique — now called investigative genetic genealogy — has since been used to solve hundreds of cold cases. Many people celebrated this as a triumph of science in service of justice, and in one sense it was. But it raised an immediate and uncomfortable question: every person whose DNA sat in that database had consented to connecting with long-lost cousins, not to becoming an inadvertent informant in a criminal investigation. GEDmatch subsequently updated its terms so that users had to opt in to law enforcement searches rather than opt out. But this episode exposed something the genomics industry had largely avoided confronting — that the downstream uses of your genetic data are essentially impossible to predict or control at the point of submission. DeAngelo's distant relatives didn't solve the case knowingly. They simply existed, biologically, in a database. That was enough.
Why It Matters
You might not have strong feelings about genomics right now — perhaps you've never used a testing kit, and personalised medicine feels like something that happens to other people. But the infrastructure being built today will shape the choices available to you, your children, and your wider family for generations. Understanding that genetic data is fundamentally relational — not individual — changes how you might think about consent, about what you owe your relatives before making certain decisions, and about how you evaluate the promises companies make about privacy. It also reframes a broader question worth carrying into everyday life: in an age of networked information, how much of 'your' data is actually only yours? Genomics just makes that question unusually visceral, because the data in question is written into your cells. The ethical discomfort here isn't a reason to fear science. It's an invitation to think more carefully about who gets to tell your story, who else that story belongs to, and what kind of oversight structures we actually want governing the most intimate information that exists.
A Question to Ponder
If your genetic data is partly your relatives' data too, who should have the right to decide whether it gets shared — and what would a genuinely fair consent process even look like?
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