Mike,
I thought I was talking about secular equal protection! Where did I mention religion?
While "race" and "gender" are obviously not exactly the same thing, they are both an attribute that should not be used to promote unequal treatment under the law. You haven't pointed out how the analogy fails, and I think it is a fairly apt one.
I believe that civil marriage is not about procreation (or even about sex). This is proven by the fact that barren different-gender couples are still allowed to marry. This percentage of the population may even rival the gay percentage, in size. And of course, many marriages result in no children, whether it is biologically possible, or not. For example, many people in second marriages, and/or who marry at an advanced age. In your religion, a different view may be taken, but we are talking about the political realm here.
Perhaps it is unfortunate that government licensed civil marriage co-opted the name "marriage" from religion and the common law, but that is the way the word is used now. When everyone agrees on a new word for civil marriage, as applied to everyone equally, then I would be happy to use it: "civil marriage" is as close as I can describe what we are talking about.
Separate is not equal. I haven't heard anyone suggesting that (straight) civil marriage be called a 'domestic partnership'; one reason being that everyone instinctively knows that domestic partnerships are not the same as civil marriage.
Rich