Have you seen this new technology? Time Magazine rates it 2008 invention of the year. It's DNA testing that tests your DNA to see how it influences 90 diseasesand traits. It's not marketed to adoptees but of course that's the first thing I thought of. Not only does it tell you what diseases you're likely to get but also what your heritage is although I imagine it's limited to continents not countries.
I did think of one down side. Do you really want your DNA on the Internet on a site that's linked with Google?