"If you allow two women to marry how does it change the value of Gold?"
Gold and copper was the allegory - either you are mentally deficient or just being facetious. Traditional marriage is "gold" and homosodomite union is "silver" - the two are not of equal value. Traditional marriage provides the best method of producing and raising children, and has proven its value to society for several thousand years. Homosodomite unions provide no benefit to society and has been rightly rejected throughout history as perversion. Why should society be forced to support that which holds no value to the same degree as that which does hold value?