23andme provide a genetic testing service and the advertisement below sounds innocuous indeed heart-warming enough. It's claimed that paying for the test (it's around US$100), enables individuals identify medical conditions.
The following paper in Scientific American, however, points to an unforeseen risk with the service.
http://www.scientificamerican.com/article/23andme-is-terrifying-but-not-for-reasons-fda/
Having paid for the test, individuals may not realise that 12andme then has access to the individual's data and this can be used both for research and marketing. To explain the nature of the risks in a pithy way - one of the founders of 23andme is married to one of the founders of Google. As the Scientific American article says:
It is a mechanism meant to be a front end for a massive information-gathering operation against an unwitting public.