Content for Humans About the Content of Humans

The pitch for home DNA testing could not be more succinct: know thyself, for a fee.
The need to know is treated as self-evident. But what we can actually learn is much trickier. 23andMe, for example, promises to help you know “how your genetics can influence your risk for certain diseases,” including Alzheimers, which is something one might want to know, if only to not not know. That you’re a carrier for a hereditary disease is more clearly need-to-know information than, say, your “genetic weight” — an estimate of what you are predisposed to weigh, according to a supposed average — which seems like it could provide, at best, qualified relief.