If you believe there are important reasons to test your DNA, then ask your doctor to run the tests and explain the results. Maybe your health insurance will pay for the test.  Maybe the doctor agrees that DNA testing is a good idea. In any case you have a relevant, intelligent discussion and learn something.

In addition, if the test is ordered for health care purposes, the results are covered under HIPAA – your privacy will be protected by the government and your DNA sample will not be used for someone else's benefit. This is the responsible and private way to perform the test.

I have written recently about the dangers of private DNA testing companies and concerns about police access to your DNA, but I did not realize until recently that other types of companies offer to analyze your DNA for one reason or another. So thousands, maybe millions, of North Americans are offering the core secret map of their entire physical being – providing scores of intimate details and possible blackmail material.

Stop trying to make casual DNA analysis a thing!

Some officials support my position. For example, the US military understands this, with the Pentagon recognizing security risks and advising troops not to submit DNA to consumer companies. The French authorities will fine you about $4000 if they discover you took a commercial DNA test. Regulators from the US Federal Trade Commission to the UK's Human Fertility and Embryology Authority have warned against privacy lapses – intentional and otherwise, in the commercial DNA community.

Our newsfeed runs rife with stories about companies that leave thousands of DNA samples exposed for years, companies volunteering their customers' DNA to law enforcement, and racists using DNA to test for "blood purity." We know that this recreational DNA testing industry is ruining the anonymity of the sperm and egg donation process, hurting fertility clinics in the process. In the US, life and disability insurance providers can legally use DNA readings to discriminate against you, as can nearly any other business, company or government. (the legality of DNA discrimination should be an article by itself)

So please, please, please think twice before providing DNA samples for something as frivolous as a commercial weight loss company.  Jenny Craig offers a "DNA Decoder Plan" to somehow tie their diet advice – I'll bet it involves buying lots of their prepackage food (they sell snacks when you search for their DNA program). The company claims that a DNA test can provide "Your eating behaviors and tendencies: Are you likely to crave high-calorie food?" Umm, yes. You need my DNA to answer that question? The personal nutritionist is not good enough to figure this out without keeping my DNA readings in a database? Weight Watchers – which is trying to rebrand as "WW" – is now offering a "DNA Diet Plan" for $99. Do we think Oprah Winfrey contributed a swab?

DNA-driven dieting is one of those concepts that seems like it should provide useful information that you couldn't get any other way.  It doesn't. Scientific American is very clear. Based on several scientific tests, including a rigorous $8 million study, Matching DNA to diet does not work. Scientists in this article said that while matching weight loss methods to DNA "just looked so cool back then" but found no difference in weight loss between people whose diets "matched" their genotype and those that didn't.

An app from Advanced Genomic Solutions tests your DNA to provide "customized" diet and exercise advice, making the multi-step jump from a DNA sample to a set of likely physical traits to how those traits can be expressed in food and calisthenics. The app works with wearable tech like Fitbit. Deanna Church, a geneticist for a biotech company said ""For complex traits, we just don't understand enough to be able to look at someone's DNA and make predictions about sports ability, intelligence, etc," and that DNA tests claiming to do so are "all equally useless."

A company called Helix runs a full sequence test on consumer DNA – providing 100 times as much data as standard consumer DNA genotyping. Helix initially shared this information, with the donor's permission, with dozens of app companies, to interpret the donor's information for a multiplicity of purposes, primarily in the health and fitness space. Helix has already changed its business model, no longer focusing on the app store, but looking for other places to gain value from its DNA database.

Many company programs offering miraculous in-depth DNA readings are simply scams, proposing to make your kid a better soccer player with a genetically devised training regimen, or recommending the perfect wine for your genetic make-up. "An outfit called GenoPalate told a Milwaukee Journal Sentinel  reporter that their DNA demanded a diet of elk meat and passion fruit" according to a Science Alert article.

Other DNA snake oil sales including Insolent.AI who claims to use DNA to uncover "how gay you are", which prominent genetics researchers paint as "garbage." The founder of Insolent was based in Uganda, a country whose government has been considering reinstating the death penalty for same sex relationships.  Where will this information end up? Is it stored in Uganda and vulnerable to government demands? How would we know? According to Science News, "There are even kits that claim to reveal superhero abilities, or that let two friends virtually mash up their DNA to see what their offspring might look like." Do any of these companies store their data in China or Russia, where the government has the right to reach in and take anything from them?

And still, some of the greatest dangers are simply mistakes and failures.  I have already covered the problems of hacking or data loss in DNA memory banks. Bankruptcy of a consumer DNA collection company involves serious risk. For a knowledge-economy business in bankruptcy, the most significant asset existing to satisfy creditors of the bankrupt company may be the database it collected during its existence. And more companies than ever are collecting DNA databases, which could be sold to the highest bidder by a trustee to pay off debts. Or the company may simply be sold to someone with a different plan for the DNA. And bankruptcy is a formal process, but many companies in financial trouble simply dump their assets and close the doors.

Wired magazine addressed this concern with an article about Icelandic DNA tester DeCODE Genetics, which claims to use DNA to calculate a consumer's risk for cancer, Alzheimer's disease and other maladies. DeCODE warned investors that it was running out of money and it filed for bankruptcy in Delaware. It was bought by Amgen in 2012, but private equity firms also expressed interest. How would they have exploited the DNA database if private equity had won the bidding war for DeCODE?

And we haven't covered the megalomaniacs like the late Jeffrey Epstein who hoped to use DNA to create his own race of people. To that end, according the New York Times, Epstein "hosted buffet lunches at Harvard's Program for Evolutionary Dynamics, which he had helped start with a $6.5 million donation." To these scientists and others "Mr. Epstein wanted to talk about perfecting the human genome. Mr. Epstein said he was fascinated with how certain traits were passed on, and how that could result in superior humans." What could he have done with millions of DNA samples if he instead decided to buy one of these many companies collecting DNA? Commercial eugenics is not necessarily illegal in the U.S. or elsewhere and could be a realistic outcome of all of these casual DNA donations.

When someone sends a DNA sample to a private company, the information is NOT protected by federal law, even in the most rudimentary sense. The important information may end up in the hands of a hostile government, a financier with different ideas about how to make money from the data, or even an evil rich person with designs on affecting genetic change like Jeffrey Epstein. It may be lost or hacked. And whoever holds your DNA knows more about you than anyone has a right to know.  More than you likely know about yourself.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.