"Regardless of the name given to it, the state’s promotion of any pairing of adults as the functional equivalent of marriage would eliminate in law and weaken in culture the ideal that children should be raised by their married, natural parents. The public meaning and purpose of marriage would be ended; marriage would be redefined as merely a private relationship of consenting adults, and parenthood as merely a legal status applied to those who choose to take responsibility for a child. The social function marriage plays in society — providing children with their natural mother and father — would be lost. . . .
"No matter what, the law will teach. Either it will teach that marriage exists as a natural institution with the public purpose of joining one man and one woman as husband and wife, ready to become father and mother to their children; or it will teach that marriage (or whatever we now call it) is just a creation of the state meant to recognize adults’ private sexual choices and fulfill their desires. Neither option is neutral. And, contra Kmiec, neither is sectarian. But, for children and for society, only one is sound."
Ryan T. Anderson, "Preserving marriage in substance, not just name: the Prop 8 debate is not a clash between civil liberties and religion," National review online, 11 March 2009, italics mine. "be[ing] raised by [one's] married, natural parents"--even just that--has taken, of course, many forms. But Anderson is still basically right, it seems to me.