personally... i hope they are both his... it could really lend itself to some deep stories and personal conflict for bats that really hasnt been explored... all of a sudden, hes got a family... he has children... and hes been an absentee father... not his fault, but he has... how would he make it up to his son? what kind of example would he try to set for his daughter? how would he handle talia hiding his son from him? how would his son react to his daughter? would he rethink his methods? batman has never been afraid to face death before... but now that he has children, would he want to take those same risks? he knows how it feels to lose a father, would he risk putting them through that? why? or why not? lots of great character development to be had here...