The age of consumer genomics has arrived. Nowadays you can send a vial of your spit in the mail and pay to see how your unique genetic code relates to all manner of human activity—from sports to certain diets to skin cream to a preference for fine wines, even to dating.The most widespread and popular companies in this market analyze ancestry, and the biggest of these are 23andMe and AncestryDNA, both with more than five million users in their databases. These numbers dwarf the numbers of human genomes in scientific databases. Genetic genealogy is big business, and has gone mainstream. But how accurate are these tests—truly?
