"One of the things marriage historically was, and essentially before the pill[, was a protection of the lineage, children = for procreation] . . . the vast majority of sexual acts in this country, 99.9% are non-procreative. We are all sodomites now. That's what sodomy means. It means having sex without wanting to have a child. So the entire society is that way." --Andrew Sullivan arguing for the legitimization of gay marriage.
As I've often argued, the legitimization of sexual acts that are non-procreative inevitably leads to the legitimization of homosexual sex. The legitimization of marriage upon principles of a loving commitment/covenant apart from procreative sex is to make an argument toward the legitimization of gay marriage.
What that means is this: Either the Bible isn't really against homosexuality and gay marriage because it is non-procreative, or it is also against the non-procreative sexual acts produced by contraception.
The only way out of the above is to argue that the Bible endorses only sexual activity with a single person that is sometimes open to being procreative but doesn't have to be at other times. The questions then become, Where is this distinction in the Bible, and Why can individual non-procreative sexual acts be considered moral, but not a relationship made up entirely of individual non-procreative sexual acts?