What's the difference between an 18-year-old girl slinging lattes 30 hours a week at Starbucks for $5 an hour and a middle-aged man who has put in years behind a desk working for their country? Well, other than a potential latte-quality divide, the difference is this: If both of those people happened to be married to a person of the same gender, one of them would get medical benefits. The part-time,...