Don’t Believe the Hype About Direct-to-Consumer Genetic Testing

Matthew Nisbet, PhD
May 23 · 6 min read

Our belief in genetics is light years ahead of what science can offer

In the nearly two decades since scientists announced in 2000 the first map of the human genome, news headlines have proclaimed a gene for a myriad of human traits including the “fat gene,” “laziness gene,” the “love hormone gene,” the “marriage gene,” and the “God gene.”

These stories tend to re-define the wickedly complex trajectory of life in terms of genetic destiny, downplaying the relevance of a multitude of social, environmental, and behavioral factors.

The strong genetic determinism that dominate’s today’s popular culture originates within science itself, argue bioethicst Timothy Caulfield and communication scholar Celeste Condit in a 2012 article. In the quest for prestige, funding, and profit, scientific institutions too often have sacrificed complexity, uncertainty, and truth.

Under immense pressure to demonstrate societal benefits and commercial
value for their publicly funded research, universities and research institutes engage in over-promising in grant proposals and over-selling in research articles and news releases.

Such messages are picked up by journalists, some of whom further twist them to add drama, gain attention, and to spread across social media. Private companies amplify the hype, employing narratives from science and the media as further grist for their marketing mill.

As a consequence of this cycle of hype “our perception of genetics is light-years ahead of what is currently achievable,” Caulfield tells viewers in a recent episode of his Netflix series A Users Guide to Cheating Death.

The cost of sequencing an entire individual’s human genome has dropped from a few hundred million dollars in 2000 to less than a thousand dollars today. Even cheaper and faster are an expanding range of services offered by direct-to-consumer genetic testing companies.

Instead of sequencing an individual’s entire genome, these companies offer consumers the opportunity to search for genetic markers of traits and diseases. There are an estimated 246 companies offering direct-to-consumer genetic tests, according to a 2016 analysis by Oxford University’s Anelka Phillips.

Despite the uncertainties specific to common diseases, genetic testing companies heavily promote their ability to provide information about our health future.

Companies market services that claim to provide reliable information about disease risk, ancestry, athletic ability, child talent, nutrition, and even personalized beauty creams, compositional music, romantic partners, and wine varieties.

Any consumer with $200 to spend can purchase a genetic test online, receive the test by mail, personally collect and mail back the DNA sample, and access the results online. Even dogs can be genetically tested for their “wellness needs.”

But Caulfield warns that consumers should be deeply skeptical of claims that “we can use genetic information to tailor these really complex human traits that have lots of genes involved, experiences, memories” that combine in unknowable ways to influence our lives.


Among genetic testing applications, it is detection of disease risks that Caulfield and other experts warn is the most problematic. More than 130 companies currently offer health risk–related genetic testing, but such tests are of dubious value.

Researchers have yet to uncover genes that provide highly predictive information about the probability of common diseases such as heart disease, diabetes, and most cancers. These diseases have complicated, multiple genetic links that interact strongly with personal environment, lifestyle, and behavior, explains Caulfield in his 2012 book The Cure for Everything.

The exceptions are a handful of rare diseases that are directly caused by a specific, single-gene mutation such as Huntington’s disease or cystic fibrosis. In this category, the best-known genetic testing “success” story is the identification of the BRCA 1 and BRCA 2 mutations, which are present in less than 1 percent of the population and can dramatically increase the chances in some individuals of breast and ovarian cancer.

Despite the uncertainties specific to common diseases, genetic testing companies heavily promote their ability to provide information about our health future.

When Caulfield, for example, tested his DNA, the results he received indicated that he had a 0.4 percent chance of developing celiac disease compared to the 0.1 percent population risk. He also had a 0.5 percent chance of developing multiple sclerosis (MS) compared to the 0.3 percent population risk, according to the company’s estimates.

But when placed in comparison to the risks presented by driving, sun exposure, smoking, drinking, or obesity, Caulfield’s 0.2 percent greater risk of developing MS was “essentially lost in the wash of risks associated with life,” he noted.

The lack of available professional guidance and counseling is all the more serious when prospective parents obtain direct- to-consumer tests.

The need to place genetic test results in context is a second major problem
with direct-to-consumer services. Few individuals have the expert knowledge to reach the type of interpretations presented by Caulfield.

If ordered by a doctor or genetic counselor by way of a local hospital or lab, a patient would be able to review the results with a qualified professional who could provide guidance on how to interpret and manage the risks — if management was needed at all.

But when an individual orders a genetic test from a company and receives
the results online, they are left to rely on their own knowledge to interpret,
cope with, and act on the results. As a consequence, an individual may develop a misguided, fatalistic attitude.

They may become depressed, holding a false certainty that they are likely to
develop a serious disease, a belief that can affect every other part of their life.

Or if they erroneously believe they are bound to develop heart disease or obesity, the patient may reason they might as well live it up and eat anything they want, stop exercising, and so on.

The lack of available professional guidance and counseling is all the more serious when prospective parents obtain direct- to-consumer tests, so-called “carrier tests,” evaluating the risks of their future children being affected by a serious illness or disability.


Privacy and informed consent are also a major concern, especially in light of recent revelations about illicit sharing of data among major social media companies.

Similar to joining a social media platform, notes Oxford’s Philips, most genetic testing companies offer consumers a lengthy, online “clickwrap” contract that is easily skimmed, if read at all, calling into question whether adequate informed consent is obtained from consumers or if they are even aware of how their personal genetic information is being stored, shared, and used.

These questions deeply matter because the business model of most genetic testing companies is premised on a Silicon Valley–inspired model considering human genetic information “digital big data to be browsed, uploaded and shared by consumers and companies online,” write sociologists Stuart Hogarth and Paula Saukko.

The main pitch made by genetic companies — that if an individual
is aware of their genetic risk for disease, they will take action by adopting
a healthier lifestyle — also stretches the truth.

As Caulfield details, individuals rarely change their lifestyle based on
adverse weight, cholesterol, or glucose levels, measures that in most cases are far better predictors of related disease outcomes than current genetic tests can provide.

Even when patients suffer a heart attack or undergo bypass surgery
or angioplasty, points out Caulfield, only about a third of patients according to studies follow doctors’ recommendations by continuing with an exercise regimen a year after the event.

Genetic testing companies rely on databases constructed by past consumers of their services, making the pool of genetic information by which to offer scientifically valid results related to racial minority groups questionable.

Not surprisingly, a meta-analysis of available studies on the effects of genetic risk information warns that “expectations that communicating DNA based risk estimates changes behavior is not supported by existing evidence,” and that genetic tests should not be used on the “basis that they motivate risk-reducing behavior.”

Many of the companies that offer disease risk information also sell testing
specific to ancestry, an option that is gaining in popularity. When a person
receives unexpected information about their ancestry, writes Phillips, it can often have profound effects on conceptions of self-identity in ways that
twist and confuse differences between race, culture, and other factors.

Tests specific to Native American or African American ancestry are also increasingly popular. But genetic testing companies rely on databases constructed by past consumers of their services, making the pool of genetic information by which to offer scientifically valid results related to racial minority groups questionable.

For example, among past consumers on file at one of the largest private databases, notes Phillips, less than 1 percent
had identified as Native American and less than 3 percent as African American

Wealth of Ideas

Knowledge-driven stories for the optimistic, curious, and introspective.

Matthew Nisbet, PhD

Written by

Northeastern University professor writing about science, politics, and a more focused life at Medium’s www.wealthofideas.org.

Wealth of Ideas

Knowledge-driven stories for the optimistic, curious, and introspective.