I work in clinical genomics / bioinformatics, and I think the current health-related results that companies like 23andMe offer are pretty misleading. They look

I work in clinical genomics / bioinformatics, and I think the current health-related results that companies like 23andMe offer are pretty misleading. They look only at a few specific genomic coordinates that are known to be contain pathogenic variants, but chances are if you have the associated disease you don't have a variant at one of those few select locations. Because of this, a negative test result does not mean someone isn't at risk for the condition. I think this nuance is likely lost on most customers. (There are certain diseases that are associated with just a few gain-of-function mutations at well characterized sites, these would be better candidates for testing of the sort 23andMe does - but that's not what they are offering in general.) The paradoxical nature of genetic variation, especially deleterious variation, is that most of it is very rare. Even with today's massive genome sequencing efforts it's still common to find variants that don't exist in ANY previously sequenced genome. Looking only at just a few sites will rarely get you the whole story.