DNA testing was once an activity reserved for bio-hackers, specialist consultants and sci-fi movie plot lines, but today industry estimates suggest that the number of people keen to unlock the secrets of their genome is rising exponentially every year.

MIT Technology Review estimated that, as of February 2019, more than 26 million people worldwide had taken one. What’s more, in 2018 more people took a DNA test than had done so in all previous years combined; the surge in numbers of ordinary people wanting to find out more about their health, ancestry and the secrets of their DNA shows no signs of abating.

This isn’t surprising. In recent years there’s been a big increase in consumer interest in health and well-being, and a corresponding increase in the number of DNA and health-testing companies entering the market – from those that tout the health benefits of sending off your spit in a tube through to those focused on the promise of unlocking the secrets of your ancestry.

But despite the growing popularity of these tests, they’ve been called into question for inaccuracies, for providing misleading information and over privacy concerns, with questions being asked both about how data about people’s DNA is used, and whether the testing methods are as watertight as the major testing companies would have us believe.

So, before you spit into a tube or prick your finger in the hope of discovering something life-changing, let’s take a closer look at the DNA and health-testing market, and find out what experts have to say about whether all the hype is justified. 

The DNA testing market 

When it launched in 2006, 23andMe was one of the first DNA testing kits aimed at consumers. Fast-forward to the present day and there are several different options available, including Ancestry, MyHeritage and Living DNA. 

There’s also another group of tests that tend to get lumped in with DNA tests, but which don’t necessarily analyze your DNA. Instead, they’re marketed as ‘health tests’, and promise to provide information on things such as your cholesterol levels and liver function, by analyzing your blood and microbiome. These include Thriva Health, DNAFit and Atlas Biomed. 

Whichever test you opt for, the process is similar. You send off a sample of blood or saliva, or a mouth swab, which is tested, and you can then access your results via an online dashboard four to six weeks later. 

The results you get will depend on which test you opt for. For example, MyHeritage claims to “uncover your ethnic origins and find new relatives”, whereas 23andMe offers options to reveal health data, ancestry data, or both. 

Which option you choose, therefore, will depend on what information you’re after. Some people are motivated to find out more about their health, but it seems there’s an increase in the number of people hoping to learn more about who their ancestors are and where they’re from. 

But that’s not all. Now that more and more of us are getting access to data about our genes, there’s been a growth in third-party websites that offer to reanalyze that data, and serve up additional information. 

For example, you can get your DNA tested with 23andMe, download all of your raw DNA data, and then upload it to a site like Promethease, Gemonelink or GEDmatch. These services provide further analysis, and can tell you even more about yourself, including which diet best suits you, as well as which medications you might need to avoid.

However, there’s little oversight from the same kind of regulation that governs DNA tests on these third-party sites. This means the results might be more interesting, but there’s less guarantee they’re accurate or that private information about your DNA is safe. 

As you’d expect, delving into the depths of the science behind what makes you ‘you’ can unearth some fascinating insights and potentially life-changing information. 

“I found out I have a strong Jewish background, which I didn’t know,” journalist Holly Brockwell told TechRadar. 

“I hired a genealogist to try and get to the bottom of it, but my family tree shows no Jewishness,” Brockwell says. “I think that means someone cheated on someone.”

Not only was this information a surprise, but it helped Brockwell piece together information about Tay-Sachs disease – an inherited disorder that’s common in those of Ashkenazi Jewish descent.

“I found out I had Tay-Sachs years back when I was getting my eggs tested for donation,” Brockwell explains, “but I didn’t know anything about the Jewishness until 23andMe, and then the Tay-Sachs made so much more sense.”

The rise in DNA testing has also brought together relatives who were separated by estrangement, revealed family secrets like affairs, and unearthed information about adoption and egg or sperm donation. We spoke to Katy from London, who told us that taking a DNA test enabled a relative of hers to find out the truth about their upbringing. 

“After getting my DNA results back from Ancestry.com, I was unexpectedly contacted by someone related to me,” Katy told us. “This person had been adopted as a baby and was searching for information about their biological family.”

“I was the first fairly close blood relative they had found. We shared information, checked relatedness with other members of my family registered on Ancestry.com, and searched genealogical records until we were able to ascertain who their biological parents and siblings are. It was an emotional journey and I was honored to be part of it.”

These stories are becoming increasingly commonplace. Numerous cases have made headlines over the past few years, like that of Dani Shapiro, who found out through a DNA test that her father was not her biological father or of Barbara Greenberg, who had been conversing with a likely half-sister through a DNA testing site, only to have her break off contact after Greenberg shared the story with her family. 

Many of the most popular DNA tests warn potential customers about the potentially shocking or unpredictable effects of the results they provide. “You may discover unexpected facts about yourself or your family when using our services,” warns Ancestry’s privacy statement. “Once discoveries are made, we can’t undo them.”

Most people will likely not be surprised by DNA results, but it’s always worth considering the implications of finding out facts about your background or family tree that you didn’t know – and that you maybe didn’t want to know.

The same can be said for health tests or DNA tests that offer health data alongside an ancestry service, like 23andMe and MyHeritage. The results can tell you your risk of developing genetic conditions, such as breast cancer and Alzheimer’s, as well as whether you’re a carrier of particular conditions, such as Gaucher disease or cystic fibrosis.

The downside of delving into your DNA: privacy

There’s no shortage of stories about the ancestor secrets that are uncovered and the health conditions that are revealed through DNA tests, but that doesn’t mean there aren’t issues around the accuracy of the results, what we can do with all that data, and how it might be used in the future. 

One of the biggest concerns is privacy. It doesn’t take much imagination to consider the negative implications of companies getting hold of information about your DNA, whether it’s insurance companies, health providers or advertisers.

Over the years there have been a number of DNA-related data leaks. One of the most serious involved health and fitness DNA testing service Vitagene, which left thousands of client health reports exposed online for years, while one of the most popular DNA services, MyHeritage, admitted to a security breach in 2018 but claimed DNA data wasn’t accessed, only information about users – which still doesn’t exactly inspire confidence.

Obviously people need to shop around and choose DNA tests that are reputable, but that does mean the onus is on consumers to make the right decisions and, crucially, read the small print. 

We asked Professor Bill Newman, a professor of translational genomic medicine at the Manchester Centre for Genomic Medicine at the University of Manchester, UK, and ex-chair of the British Society of Genetic Medicine, what people can do to safeguard their data and protect their privacy. “They should read the paperwork,” he said. “They need to ask who will their data be shared with? Will this be anonymized? Or available in an identifiable way?”

We asked a spokesperson from 23andMe about how the company addresses issues around the privacy of DNA data. “To protect customer privacy we use a range of physical, technical, and administrative measures to safeguard personal information,” they told us. “Customer data is de-identified, meaning personal information such as name, email, and other contact information is stripped from your genetic information, and the two data sets are stored separately.”

However, even with robust privacy policies in place, there are widespread concerns about the safety of DNA data in future.

“As it currently stands, most at-home DNA tests purport to keep individual data private and have robust privacy policies,” Marcus Vass, Co-Head of Digital Health Group at tech-focused international law firm Osborne Clarke told us. “However, maintaining this privacy is becoming increasingly difficult.

“DNA data is high-value, because, unlike a credit card, our DNA is not something we can change or cancel. No matter how detailed the privacy policy, there is always the risk of a breach. It’s only a matter of time before hackers are able to get their hands on DNA data.”

Aside from concerns surrounding DNA testing companies themselves, another issue is what could happen to data if it’s later uploaded to third-party websites or shared with larger databases, even if that’s done anonymously.

“Most of the leading genetic testing companies allow users to download their genetic data, stripped of personal information; a process called ‘de-identification’,” Vass said. “Users are free to upload this de-identified data to a public genealogy database, and here is where the greatest risk lies. ‘Re-identification’ of supposedly anonymous DNA data from public genealogy databases is increasing, as highlighted by the well-publicized identification and conviction of [California’s] Golden State Killer – someone who had not even used the service.” 

According to a recent study, using the DNA data from 1.28 million individuals available on a public database, researchers could correctly identify a third-cousin or closer match in 60% of searches for individuals. What this means is that even if you don’t do a DNA test yourself, it’s possible that there’s enough information about you available in an online database because enough of your relatives – whether close or distant – have. 

This data has already helped authorities to find criminals, including the Golden State Killer, as well as the killer of Angie Dodge in Idaho, USA, which also resulted in the exoneration of an innocent man who’d been in prison for more than 20 years for her murder. Meanwhile, DNA testing company Family Tree DNA revealed earlier this year it would work with the FBI to allow agents to search its genealogy database in an effort to solve violent crimes.

Although using DNA test results to help find criminals may sound like a good use of the data, privacy advocates are concerned about what this means for the safety of personal data in the future – and who gets to say what should and shouldn’t be handed over to law enforcement. 

One answer is to always allow people to opt-in to sharing their data, which Family Tree DNA says it does. However, the study above shows that although some users may submit their DNA profiles willingly, relatives identified via the genetic code of those willing subjects have not.

Should you send your spit away for testing? 

There’s no denying that DNA tests are attractive to individuals keen to find out about everything from their ancestry, to their predisposition to serious health problems, to indulgent information about their eye color and personal tastes. 

But what about the concerns? We asked Newman what he thought about the future of DNA testing. “They are here to stay, and clearly there is an appetite for them,” he told us. “People are curious about their ancestry, and for [DNA tests] to be used in this way is benign.”

But he warned that when it comes to health matters it can be an entirely different story. “When it comes to providing predictive health information we should be more cautious. Firstly people need to understand what is being tested, what the risks really mean, and, if an increased risk of a health problem is established, what can be done to reduce the risks.”

Like many medical experts, Newman says it’s still best to go straight to your doctor if you’re worried about your health; after all, most consumer DNA tests come with disclaimers about how they’re not proper diagnostic tools. “If an individual is worried about their risk of an inherited condition in their family they should seek the advice of their GP who will refer to the local genetics service if appropriate.” 

DNA testing has become big business in recent years and it’s no surprise, the sheer wealth of information you can find out about yourself and your ancestry – especially from the more popular tests – can be fascinating. But, everyone needs to be wary of what they’re signing up for. You’re not guaranteed to see the ancestry you expected with a few neat surprises and a clean bill of genetic health – the reality could be much more uncomfortable, shocking or, in the case of my very Yorkshire ancestry going back centuries, just a bit boring.