What is the most compelling argument in favor of marriage?

Every child should be able to say, “When I grow up and get married. . .”

They shouldn’t have to asterisk the comment:  “When I grow up and get married*. . .  *[assuming that I’m not gay]”

They shouldn’t have to utter a mouthful:  “When I grow up and get married or form a domestic partnership with the person I love. . .”

They should just be able to say, “When I grow up and get married, . . .”

Every child.