"A word that describes two people of the opposite sex who wish to live together as man and wife, and bring children into the world, as a result of having sex with each other, and to be raised by the same two people as a family, as opposed to any other 'domestic' situation." Clearly, the plural noun "breeders" meets this requirement. If the individuals involved wish to have a legal or quasi-religious affiliation as well, than they can join the rest of us under the much broader heading of marriage.