Eliminating sexual complementarity from the legal definition of marriage necessarily means formally declaring that marriage has no inherent connection to reproductive potential. Those who seek to redefine marriage—marriage revisionists—claim that because many marriages don’t result in children, the issue of reproductive potential is irrelevant.
But reproductive potential is the only reason the government is involved in marriage. The government is involved in the marriage business precisely because the union of one man and one woman is the type of relationship that naturally results in children. And the government has a vested interest in protecting the rights and needs of children upon whom the future health of any nation depends.
Marriage revisionists who claim that marriage has no inherent connection to reproductive potential and is constituted solely by deep emotional bonds shift the focus from the needs and rights of children to the desires of adults. In so doing, marriage revisionists erode the only justification for government involvement in marriage.
Further, marriage revisionists have no reason to prohibit plural marriage or incestuous homosexual marriage and no way to explain why marriage should be permanent and exclusive.