Here's a thought. If marriage is defined as a religious ceremony, and a civil union is simply a partnership of individuals for joint recognition by government for economic advantage, what is the difference between a civil union and a business partnership or corporation? If my father wills his property to be divided equally between my sister and I, but we want to keep it a whole entity, with equal say as to its use, we could accomplish it by forming a partnership or LLC in which we are equal owners. Why couldn't we also form a civil union and accomplish the same thing.
Is there some assumption that if my adult sister, my adult brother, and myself are all living together in the same house and sharing our joint heritage equally under civil union that we are somehow engaging in some kind of incestual bisexual threesome, but if we form a 3 owner LLC or non-profit we are not? Even if we were, is that the government's concern?
In reality, the three of us are all in heterosexual marriages. My brother under the Lutheran church, myself under a non-denominational minister, and my sister in a civil union.
Growing up, the farm closest to ours was owned by two old men in their 70's who had never married. They had a partnership business which was registered with the State as agricultural property management. My Dad leased some of their land for hay, grain, and legume production. Were they gay? Is that why the never married, and to my knowledge never even had girlfriends? Possibly. Does it matter as far as the state is concerned? NO! Did anyone in our small community care or ask them about it? Not to my knowledge.
What consenting adults do in the privacy of their own homes is between them and god, unless it deprives someone else of life, liberty, or property.
I feel the same way about polygamy as I do about homosexuality. To each his own, it's none of my business, and there are churches which recognize both as spiritual relationships.