I think you hit it right with calling gay marriage a union. It is a union or coupling but not a marriage. If you do woodworking then you might understand where I come from on this. When joining wood or marrying joints you have male and female or pins and tails. Tabs go into slots. If you have the same tabs or slots then you have a butt joint, no pun intended. I will not get into how strong a butt joint is or not. Look at automobiles, every try to put one together with just bolts or nuts. Won't work.