Genetic Testing for Athletic Performance
The test measures the gene ACTN3, which produces a protein necessary for powering fast-twitch muscles. Athletes typically have a high level of this protein, so it stands to reason that anyone with it would have at least some athletic prowess. However, the test is controversial because, critics say, it would close the door on less genetically endowed athletes who have other characteristics (stamina, coordination, mental discipline) that would compensate for the lack of that protein. Similarly, an individual with strong ACTN3 might lack the capability -- or even the desire -- to be a great athlete. There is also the risk of putting children on a "fast track" toward athletics against their will, while discriminating against kids who don't test as well yet have a true passion for sports.
This is yet another clear case of technology jumping ahead of society. We have the means to make these kinds of measurements, but we don't yet know how to handle the consequences.