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Guest post: Whose genes are they anyway?

The case of identical twins with different views about having their genome sequenced raises a series of privacy issues

Kat Arney is a London-based science writer, broadcaster and presenter of the monthly Naked Genetics podcast

As a gene geek, it brings me joy to see that genetics is now (almost) cool. More of my friends are getting their genomes “done” through services such as the Google-backed 23andMe. But amid all the excitement of boasting on Facebook about how Viking you are, there are some major issues around data privacy and security that we all need to start thinking about.

I don’t want to re-tread the well-worn arguments around 23andMe’s data privacy policies and monetisation of its impressive genetic archive. And if you want to get your genome analysed without giving away your personal information, there’s a rather convoluted way of doing so for the more technically minded gene-curious out there.

Rather than focusing on the responsibilities of the companies and research organisations collecting and handling genetic data, I want to turn the issue back on the public. Most people would probably agree that their genes belong to them, and that information about the contents of their genome shouldn’t be indiscriminately flogged to corporate interests or the government.

But this isn’t quite true. Your genes are not just your genes. You share a significant proportion of them with your blood relatives. Information that you find out about your health and ancestry doesn’t just apply to you – it might well apply to the people in your family too. Do they have a right to know about serious disease risks that you find lurking in your DNA? And what about evidence of complicated family situations such as adoption or what is euphemistically called “misattributed paternity“?

According to 23andMe’s own information pages:

Everyone has different tolerances and preferences for learning information. You might be surprised by a family member who would prefer not to know something you feel is important to share. At other times, you may learn something about yourself, your family, your ancestry, or health-related associations with your genotype that you would prefer to keep private. You may find yourself having to weigh sharing such information with other family members against your own desire for privacy – or their desire not to know.

But is this kind of “Careful now!” warning enough? In the case of identical twins, their genetic sharing is almost 100 per cent. If a twin decides to have their genome analysed, they are also finding out private information about their sibling too. So what happens if they don’t want to know? It might sound like a far-fetched scenario, but this decision recently cropped up for identical twins Samantha Schilit and Arielle Schilit Nitenson, who wrote a paper about their experience in the Journal of Genetic Counselling.

Samantha – a US-based neuroscience PhD student – sent her DNA off for sequencing without considering that she was in effect also sending her twin sister’s genome in the same tube (something that also wasn’t mentioned by her doctor when ordering the test). Arielle was very unhappy about this decision. She was concerned about who would have access to the data – and whether it could be used by insurers or employers to discriminate against her – and did not want it used for research. Ironically, Arielle’s genetic data became vitally useful to her during her first pregnancy, as it revealed important information about her personal risk from different delivery and pain relief options.

Arielle and Samantha eventually managed to come to an agreement between themselves about how to handle and disclose their shared genome, but the issue of genome sequencing involving identical twins (and higher multiples) is an ethical minefield. Although it’s more than a decade old, the World Health Organisation’s 2003 Review of Ethical Issues in Medical Genetics provides a short paragraph of guidance:

If, after extensive counselling, they cannot agree – one wishes to be tested and the other does not wish to know the results of the test – the professional should proceed to test the person who requested it, provided that (1) both parties are fully aware of the possible consequences of testing one individual; and, (2) the party who does not wish to know the test result of her/his twin has had sufficient time and opportunity to protect him/herself against learning the result inadvertently. To refuse to test the twin who requests it would be to deny the uniqueness of that twin as a human being.

Although twins are a relatively rare situation, we still share a good percentage of our genomes with our closest blood relations. And as more people seek information about their genes, whether for recreational ancestor-chasing or medical reasons, the issue of who to tell – and what to tell them – is only going to grow. Population genetics expert Dr Susan Wallace and her colleagues at the University of Leicester argue that 23andMe-style “think before you sequence” self-regulation isn’t enough, mainly because people don’t read the small print:

“The level of understanding that clients possess regarding genealogy information is questionable and it is not known how many actually read the terms and conditions or privacy statements provided… Do relatives understand the possibilities? Is one person’s consent enough or is something more needed?”

Instead, Wallace proposes the need to investigate and develop what she calls ‘generational consent’, which should include an individual’s relatives in the decision whether to take part in any genetic analysis. But while ethicists ponder what this might look like and how it will work, genetic technology (not to mention marketing) is racing ahead. Thousands of people around the world are busy spitting in tubes and popping their DNA in the post to see what’s in there, without considering the ethical and privacy issues for members of their families.

I don’t want to see progress in genetic research stall due to excessive red tape, or prevent people finding out potentially life-saving information about their health, but if you’re considering having your genome done, the ethical thing to do is to discuss it with your relatives first.

Kat Arney’s first book, Herding Hemingway’s Cats: Understanding How Our Genes Work (Bloomsbury Sigma) is out now


Sounds interesting, but after reading the link “convoluted way of doing so” it just seams to much work to keep it private vs what you learn. It won’t change anything about my life to know it, but it certainly is going to give up privacy or be a PITA to get this entertaining data about ones self. Might be easier, and funnier to have a friend of the opposite sex and different race send in your sample…


Since large sums of money is involved, I’m sure it’ll be abused and mis used. Insurance companies would love to know this stuff… :)


We actually need someone like the EC to take this up and propose laws that prevent genetic discrimination pretty quickly before this we get much further on this. We also need laws protecting data against de-anonymisation techniques. Why? Because if you take medical data that (for example) is anonymous but has geographic data such as post code, then combining with other data sets makes it possible to identify the people. In the UK, a postcode may often identify only a few houses – usually 30 maximum, but less in country areas – in my case it is about 10 properties. With there being only two people under 20 in these properties, you would have a high chance of identifying anyone with a young person’s disease and 100% chance of identifying a teenage pregnancy.
So we need strong legislation before business has built up databanks on our personal characteristics and it is too late to prevent the misuse of personal information e.g. genetics over which we have no choice.


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