David Epstein, writer for ProPublica and author of The Sports Gene, talks with EconTalk host Russ Roberts about the book. Epstein discusses a number of the ideas in the book including what we have learned about the nature vs. nurture debate, the role of practice in achieving mastery, why a small part of Kenya produces so many champion marathoners, why major league all-stars can't hit a fast-pitch softball, the strange nature of body types in the NBA and why Michael Phelps's body gives him an advantage.