DNA testing itself is fraught with demarcation issues.

How do you determine what is a fair marker, a reference level that someone is native based upon their DNA?

There was a young woman whose name appeared in a NY Times article several years ago. She was a white person, from all appearances, and was denied entry to various Ivy League universities due to the demand level. She then decided on a random hunch to have a DNA test done. The results showed she has approximately 5% Asian genetic markers.

She reapplied under the affirmative action program at a well known Ivy League university (with results in tow) and was admit as an Asian student because on the application she claimed Asian ancestry. Officially, at this university she's Asian. Outside she is as white as snow.

Obviously, this pissed off a lot of people when this article came out. But it also started a rush.