The past weekend brought the news that you can now pay $149 to get your child’s DNA tested to determine whether you’ve got a future Olympic athlete or NFL Hall-of-Famer on your hands ... or a first class couch potato. The focus of the genetic test is the ACTN3 gene, which instructs the body to produce a protein, alpha-actinin-3, that is found specifically in fast-twitch muscles ... the muscles most valuable in power and speed sports. In brief, the makeup of the gene helps determine whether a person might be better suited for sports that require power and strength, or endurance, or general activity ... or none of the above.