http://nymag.com/news/features/23andme-2014-4/

A long article, seven internet pages, but well worth reading, especially the section on page six starting:

"What the conflict between the FDA and 23andMe boils down to, then, is an epistemological dispute over what counts as scientific knowledge."

The key issue seems to be whether individuals should have access to estimates of their likelihood to get diseases, in particular when the precision of the estimates is poor. For instance, suppose a person's genetic profile pointed to a rough estimate of the risk of PD double the average, and supposing that that person found epidemiological data suggesting that smoking halved the rate of PD. Then harm would be done if the person took up smoking: the possible benefits in terms of Parkinson's would almost certainly be outweighed by increased risk of cancer and heart disease. In spite of this, I support the 23andme approach, fundamentally because as adults we should be responsible for our own actions. That includes taking responsibility for what actions we take based on 23andme reports.

John