Defense of Marriage a No-Brainer!

Today oral arguments are being heard before the U.S. Supreme Court on the question of so-called "same sex marriage" and whether states have a choice to legalize it or uphold "traditional" marriage.
Unfortunately I cannot be there to defend the institution of marriage, ordained by God, but if I were this is how I would plead my case:
May it please the court. There is no such thing as same sex marriage. It is an oxymoron. Marriage is and always has been since the beginning of civilization, the union of a biological couple for the purpose of creating a human family and regenerating and nurturing the human species to adulthood. The only combination of persons capable of such a thing is one man and one woman because only a man and a woman are capable of sexual intercourse, a necessary component of human reproduction involving both male and female reproductive organs.
My opponents argue that biology is merely an incidental component to marriage, that a couple eligible for marriage should be any two adult human beings who "love" each other. My answer to that is love has never been a prerequisite to marriage and although it is desirable that a husband and wife love one another, love is, in many cases, a result of marriage and not necessarily a pre-existing condition. In some cultures, a person's first encounter with their spouse is on their wedding day. Also, there are many kinds of love, including Platonic love. Under that definition, best friends and siblings should be able to marry, but that would dramatically alter and defeat the purpose of marriage as we have always understood it. There is nothing preventing two people who love each other from living together and thus they are not being denied the right to share a life with the person they love.
My opponents argue that current marriage laws discriminate against homosexuals because they are denied access to tax breaks and other legal benefits of marriage. This is utterly false. Homosexual persons have always had access to lawful marriage, that is, marriage to a member of the opposite sex. Many homosexuals in fact have married members of the opposite sex, have produced offspring, and have had what many would view as a successful marriage. Therefore, it is not true that they have not had equal access to the institution of marriage.
Thus, they are arguing for the creation of a new institution that has never existed before, a civil union between two members of the same sex bearing all the rights and privileges of a marriage union. The burden of proof is on them to prove how the two could possibly be regarded as equal or of equal value to society. But if such a case can be made for extending certain legal rights and privileges to same sex domestic partners, such issues are clearly a matter for states to decide and to regulate. But to redefine marriage itself is not within the jurisdiction of any human power or authority because it comes to us through natural law, authored by the Creator. The most any state can do is to create a vehicle for domestic partnerships that can be regulated and taxed accordingly and through which members of a given partnership would have specific rights previously reserved for family members only. But no state has the right to call such a thing a marriage in defiance of common sense.
Thus, I am asking the Supreme Court to overrule any attempt by any state to redefine marriage and to declare once and for all that marriage is what it has always been in the eyes of the law, a union between one man and one woman. God save the Court and God save the United States of America.