AP Photo Chelsea Manning I n all the fact-checking I've ever done, I never called up a source and asked, "Just making sure: You're a guy/girl, right?" Nor have I asked to see their genitals, the results of a chromosome test, or their medical records. If the interview was over the phone, I infer from the name and the sound of the person's voice. In the few instances that hasn't been enough, I've turned to Google to see if they have an official headshot that'll provide more clues, or a company bio that settles the matter. In person, you have additional data—the choice of clothes, mannerisms we've come to read as "feminine" or "masculine." In other words, reporters do what everyone else does, and it turns out to be a very un-journalistic thing to do: We go by what we see, take a guess, and assume it's right. Last week's announcement that Bradley Manning—the Army private who was sentenced Wednesday to 35 years in prison for releasing government files to WikiLeaks—is female and now wants...