Should you have your kids genetically tested? This is not a question that most parents consider—yet. However, as genetic testing becomes more common, due to the development of genetically guided, personalized health care and the growing popularity of inexpensive direct-to-consumer genetic testing services, we're nearing a point when nearly everyone will take a genetic test at some time in their lives. Increasingly, that time is likely to be childhood, when decisions about whether to take a genetic test and how to handle the resulting information are made not by the ones being tested, but rather by their parents. This may not seem like a big deal—parents already handle a lot of important personal information about their kids, including how their weight compares to average and whether they're meeting key developmental milestones on time. If genetic tests offer more information about how to help kids be healthier, that's a good thing, right?
Not always. Learning about our genetic make-up poses risks that can be tough for even adults to handle; when it comes to children, genetic testing is an ethical minefield. To help doctors, researchers, and anyone else who deals with genetic testing navigate that minefield, the American Society for Human Genetics—a major medical genetics organization—has just issued a set of recommendations on genetic testing in children and adolescents. These guidelines offer some needed clarity on a rapidly changing issue, and they raise some surprising questions that we as a society will have to face as genetic testing becomes routine.
Guidelines note that "with estimated rates of 1%–10% from various studies, non-paternity is relatively common and is therefore highly likely to be encountered in routine practice and in research."
The new guidelines answer two critical questions: Why would you want to have your kids genetically tested, and what could go wrong if you did? The simple answer to these questions is that we can now test our DNA for both medical and recreational reasons, and the results might reveal more than we wish to know. That might sound strange—can you really learn too much about your own genes? The ASHG guidelines make it clear that, in some cases, yes, you can. Knowing the results of a genetic test can have major, life-long consequences, and therefore, the ASHG argues, "informed consent to genetic and genomic testing is a core principle for which there are few exceptions." This means that rather than having parents consent to testing for their children, it's often better to wait and let the children decide for themselves when they're old enough.
Deciding whether to delay a genetic test can be a tough call, however, in the case of families in which children have a high risk of inheriting a genetic disease. If the disease is one that manifests itself in childhood, like hemophilia, then of course parents should have their children tested when it’s necessary for their child’s medical care. But when it comes to adult-onset disorders, such as certain syndromes with a high risk of cancer, the question of whether to test children becomes much more complicated. Many parents understandably want to put an end to the uncertainty over whether a child has inherited the disease. But should these children really spend their childhood knowing they have a 90 percent chance of contracting breast cancer when they’re older? Angelina Jolie famously made the difficult decision to undergo a preventative double mastectomy based on a genetic test. This is an extremely difficult decision for an adult; it’s not one a girl should have to agonize over throughout her childhood if she doesn’t have to.
Furthermore, as the ASHG points out, "informed adults make a range of choices about predictive and reproductive [genetic] testing, and thus many adults decline such testing." In fact, for some hereditary diseases such as Huntington’s disease, most at-risk adults choose not to be tested, since there is no medical treatment that will help anyway. Rather than making these decisions for their children, the ASHG recommends that, unless there are medical treatments appropriate in childhood, parents should, in most cases, defer testing until their children are old enough to meaningfully participate in the decision.
Fortunately, most of us don't have to face such wrenching decisions about a genetic test. Instead, parents now have many opportunities to have their kids tested for a different reason: recreation. More than a dozen companies now sell genetic tests directly to customers, without requiring a doctor's signature. For less than the cost of an iPhone, they will sell you genetic tests that serve a variety of purposes having little to do with major medical decisions. One of these companies, 23andme, features testimonials from its customers, who explain how the company's ancestry testing service helped them find biological parents and siblings they never knew they had. Others get tested in order to contribute their genetic information to research, or simply out of sheer curiosity about their biological make-up. Some companies will sell you diet and fitness advice that is supposedly optimized for your genetics. While most of these companies aim their products at adults, most companies will also, as one survey found, perform their tests on children if a parent requests it. In fact, one company even offers a test to give parents "information on their child’s genetic predisposition for success in team or individual speed/power or endurance sports."
Should you buy these tests for your kids? The ASHG guidelines discourage it. One of the most important reasons is that recreational genetic testing "provides information of variable accuracy and clinical validity." Many of the claims made by these companies are frankly suspect, particularly ones that offer advice on diet or sports. For example, several companies that offer sports-related genetic tests examine the gene ACTN3. A particular version of this gene appears to be associated with better performance in power sports, but the link is relatively weak and may disappear with exercise. It’s one thing for an adult to give a genetic sports test a try and, at worst, lose $150 in the process. It is something else altogether for a child to be pressured to select a particular sport based on the questionable results of a genetic test.
Questionable claims aren’t the only problem with recreational genetic testing. Sometimes the information is reliable but not exactly welcome, revealing life-changing information we aren’t expecting. The company 23andMe offers stark warnings in its terms of service, advising customers that "you may learn information about yourself that you do not anticipate." For example, some types of tests, when both a parent and child take them together, can reveal what geneticists euphemistically call "non-paternity." The ASHG guidelines note that "with estimated rates of 1%–10% from various studies, non-paternity is relatively common and is therefore highly likely to be encountered in routine practice and in research." Findings of non-paternity can be detected by some direct-to-consumer genetic tests as well. Aside from revealing unexpected family secrets, a test not taken for a medical purpose can also suggest that there is genetic potential for serious medical problems—a finding which may or may not hold up after further scrutiny. This can lead to unnecessary anxiety, as well as wasted effort and resources on further diagnostics. This is why the ASHG argues that medically relevant testing should always be accompanied by proper genetic counseling, something not generally offered at direct-to-consumer companies.
Given the increased profile of genetic testing, the ASHG guidelines might sound overly conservative and out of touch with the growing role of these tests in our society. There are currently major research projects underway to explore the feasibility of obtaining complete genetic information right at birth and making it an important part of a child's medical records. It seems inevitable that, sooner or later, genetic testing in childhood will be common. But we have a long way to go before such routine testing becomes routinely helpful—before we can be confident that newer types of genetic tests are reliable, meaningful, and accompanied by readily available counseling to help people make sense of results. These problems are solvable, the ASHG argues: "As genetic and genomic tests become more accurate and their use becomes more common, the ethical, legal, and psychosocial challenges will become more familiar and less worthy of statements of this sort." Until then, parents should think twice before having their kids genetically tested.
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