Martin Luther: The Granddaddy of the "Marriage Mandate" Movement?

"After God had made them male and female, he blessed them and said to them, 'Be fruitful and multiply' (Genesis 1:28). From this passage we may be assured that man and woman should and must come together in order to multiply... Hence, as it is not within my power not to be a man, so it is not my prerogative to be without a woman. Again, as it is not in your power not to be a woman, so it is not your prerogative to be without a man. For it is not a matter of free choice or decision but a natural and necessary thing, that whatever is a man must have a woman and whatever is a woman must have a man...
"'Be fruitful and multiply'... is more than a command, namely a divine ordinance which it is not our prerogative to hinder or ignore. Rather, it is just as necessary as the fact that I am a man, and more necessary than sleeping and walking, eating and drinking and emptying the bowels and bladder. It is a nature and disposition just as innate as the organs involved in it. Therefore, just as God does not command anyone to be a man or woman but creates them the way they have to be, so he does not command them to multiply but creates that so that they have to multiply. And wherever men try to resist this, it remains irresistible nonetheless and goes its way through fornication, adultery, and secret sins, for this is a matter of nature and not of choice."

(Martin Luther, "The Estate of Marriage", as quoted in Debbie Maken's "Getting Serious About Getting Married: Rethinking the gift of singleness")