This is a short piece (est. 37 pages) available as a kindle single or as the October 2013 selection of the online magazine Matter (readmatter.com).
It's an excellent article about genetic genealogy -- the practice of comparing ones DNA to that of others in a database in order to determine your family history or locate relatives. At first thought, it seems like a good idea, but Hughes describes how it can backfire on you, uncovering information and relationships you may have preferred not to know about. There are also privacy issues because your DNA does not belong solely to yourself; your relatives share portions of it and if you make your information available in a public database, personal information about your relatives can often be extrapolated.
This is very well written, bringing in the personal stories of a number of people who undertook such a search, with varying results. The author focused on the unexpected nature of the results, but handled it tastefully and with sympathy. My only complaint was that I wish she could have spent a little more space on privacy and legal issues.