According to the group Freedom to Marry, about 13 percent of Americans now live in a state that allows gay couples or recognizes marriage licenses issued in other states, and that percentage is certain to rise. The gist of the disagreement now isn't partisan or theological as much as it is generational. Unlike their parents, younger Americans and those now transitioning into middle age have had openly gay friends and colleagues all their lives, and they understand homosexuality to be a form of biological happenstance rather than of emotional disturbance.