It's dinnertime at the Barton household and Madilyn's turn to say grace. Holding her parents' hands, the 5-year-old races through the blessing: "God-is-great-God-is-good-Let-us-thank-him-for-our-food," she says breathlessly. "Whoa, Madilyn, not so fast," her Papa admonishes gently. "Please do it again." Twin sister Marilyn giggles as Madilyn recites the prayer again, this time slowly. This time, both Papa and Daddy smile approvingly. Night after night in their two-story Orlando home, Craig and Don Barton and their adopted daughters follow a routine familiar to millions of families. As a gay couple, Craig, known as "Papa" to his girls, and Don, the man they...