The field of genomic science is rapidly advancing, with commercial genetic tests becoming affordable and popular.

Taking these tests is simple. The company sends you a collection kit. You send it back with a saliva sample or cheek swab. The sample is sequenced and analyzed, and before long you have your results.

However, upon a closer look you’ll find commercial genetic tests come with several hidden risks, and consumers often don’t understand what they’re signing up for. Here are some important factors to consider if you’re thinking of getting one.

Ancestry tests

The most common personal genomics tests are ancestry tests, offered by companies including Ancestry, 23andMe, FamilyTreeDNA and MyHeritage.

Ancestry tests are marketed as a way to explore your ancestral origins. But since different companies use different methods, and even different “ethnicity” categorizations, you may get inconsistent results. For example, Kristen V. Brown wrote for Gizmodo about how her saliva sample produced three different results from AncestryDNA, 23andMe and National Geographic.

In another example, a 2019 CBC Marketplace experiment involved sending the DNA of identical twins to five different companies. Each company returned surprisingly…