William Saletan in Slate:
A few days ago, I wrote about a test, now being marketed in the United States, that predicts whether your toddler has more potential as a power athlete or as an endurance athlete. The test examines ACTN3, a gene that affects fast generation of muscular force. Fray poster Andrea Freiboden isn't impressed. “What a lot of crap. Just look at the race of the athlete,” she writes:
Generally, people of West African origin have more fast twitch muscles which allow intense bursts of power. This is why running backs, defensive linemen, and receivers are almost all black. We don't need any expensive test. All you have to do is look at the physique. Blacks in basketball are lean and musularly [sic] hard. Whites have softer muscles, which is why white basketball players have to rely more on skill than blacks who have the advantage of skill + great speed/strength.
Oy. I've been through this wringer before. It's true that some racial averages differ in part for biological reasons. It's also true that that this is one of them. But Freiboden is exactly wrong. Race is a less, not more, reliable gauge of physical characteristics than genes are. In fact, that's one of the chief consolations of nontherapeutic genetic testing: No matter how inaccurate genes are as a predictor of this or that ability, they're more accurate than predictions based on race. And the sooner we get past judging by race, the better.
More here.