The test is sold by a UK company called XRGenomics and all you have to do is send them some cheek skin cells. Within a few weeks they'll send you the results. So you can know whether it's worth it or not to stay on that Zumba, P90X, CrossFit, or Brazil Butt Lift routine!
More here: http://well.blogs.nytimes.com/2012/10/10/are-you-likely-to-respond-to-exercise/